Sure, less complex organisms evolve at a faster rate. In fact, the rate of evolution is really controlled by two (main) factors:
1. How fast new generations come along:
Of course, the more generations and the more mutations; the more that evolution is occurring. This explains why insects evolve so quickly - and why they're chosen for experiments.
2. How much evolving is even needed:
If you take jungle insects and put them in a desert (assuming they don't die within a few generations), they will very quickly evolve, however, if you leave them in the jungle, you won't see as many drastic changes. The crocodile is often referred to as the perfect predator because it has remained almost the exact same since the dinosaurs. Many species have come and gone but the crocodile persists. This is simply because, again, the crocodile is the perfect predator, it has no need to evolve, so it doesn't (roughly).

how certain organisms came to be the way they currently are. — Susu

Yes, I love to think about Earth's amazing creatures. In fiction, we talk about other worlds and dimensions, and all the wonderful, mythical creatures that reside there. But I feel we too seldom appreciate the animals we have here. I mean we do. People love animals. But imagine if you came to Earth from another planet and saw a zebra, a giraffe, an anglerfish, a chameleon, or any of the countless other strange earthly inhabitants. It really makes you question how "mythical" a unicorn really is...

I'll also say, I'm really not qualified to talk about this evolution stuff, but it is really interesting.

To me, evolution is a great concept and, some say, proven through many instances of observations made in the natural world. Microbes evolve to become resistant to antibiotics. There are transitional fossils and so on. I too ain't qualified but these examples give a good feel about what evolutionists mean.

IF evolution is true I believe, as everyone should, that there are limits to it. If humans are considered, our defining trait and that which should be selected for if evolution is a fact is our brain. But there's a limit to how big our heads can get and, ergo, how intelligent we can become. Of course it maynot be size that's important but some unknown structure of our neurons.

In short what I'm saying is space is limited and there's nothing we can do about it.

Another thing is we have no recourse to steer our evolutionary paths. All we can do is hope the random mutations will select the traits we need to be successful. Eugenics?

Animal breeders are a ''good'' example of how we may choose the traits we want in a population.

Moral issues pop up in selective breeding. So you have that to consider.

As for me, I think we need to concentrate our efforts in artificial intelligence. We are, after all, ''accidental'' machines born of random mutations in our genes.

What wonders may be achieved through ''intentional'' machines like AI!

If AI ever becomes a reality then we would've evolved beyond the limits of random chance in our genes.

What I'm saying is that that the limits of ''biological'' evolution need to be overtaken. With machines this is possible.

Our current situation is like a spacecraft orbitting a planet. Bound by planet's gravity well our options are limited if non existent. We need to achieve escape velocity (AI may be just the thing we need) and go where no life has gone before.

Just a pipe dream of mine.

I see them as very complex and rigid, especially to the extent that their malleability solidifies towards their surrounding environment. At the onset of evolution, simple organisms were more malleable to the variables surrounding them, so changes occur at a fast pace, but as these organisms progressed with due millions of years, their malleability became rigid which is why you don't see evolution occuring today. Not to say that evolution is not happening, it does as we speak but at a rate so slow that it is hardly ever apparent. — Susu

One of the nice things about evolution is that for the most part, it tends to - by nature, as it were - shape organisms which strike a balance between rigidity (or rather, what is called 'robustness') and plasticity. Anything too robust, will, over the long run, find it hard to cope with environmental changes. Anything too plastic won't (necessarily) be able to take advantage of the environment around it. Of course, exactly what counts as robust and what counts as plastic is itself determined by the pace of environmental change. So the animals deep under the sea are, for example, incredibly ancient and have stayed the same for a long time because their circumstances don't change much. Whereas species on land - or just in the sunlight in general - have alot more to deal with, environmentally speaking, and thus have a far faster rate of evolutionary change.

So if deep-sea species are anything to go by, I don't think it's true at all that evolution is 'harder' with currently evolved organisms. If anything, the complexity of species (spurred on by the complexity of environment) tends to encourage more, and not less evolutionary innovation. There's a reason why evolutionarily primitive organisms are all so similar (a bunch of nuclei, vacuoles, flagella, mitochondria, etc) - is because (among other things) their environments are all of limited variety. Complex creatures, on the other hand, able to do alot more (than swim around in warm ponds), also have more opportunity to make use of evolutionary novelties. This is all very broadly speaking of course, and a thousand and one factors go into determining evolutionary pace, but these are - I think anyway - the broad tendencies and strokes that characterize evolution as it stands on Earth.

If you're interested in questions like these, you might want to try a book like this, or this.

When I look at current organisms, I see them as very complex and rigid, especially to the extent that their malleability solidifies towards their surrounding environment. At the onset of evolution, simple organisms were more malleable to the variables surrounding them, so changes occur at a fast pace, but as these organisms progressed with due millions of years, their malleability became rigid which is why you don't see evolution occuring today. — Susu

I think you got this idea because you don't have a good feel for the timescales involved (that's OK, most of us don't). Life has been on Earth for about 3.8 billion years - that is, practically since the surface of the planet cooled and stabilized enough for life to be at all possible. But for the first two billion years there were only bacteria-like organisms. Only then did the first organisms of a different kind appeared, from which plants and animals would eventually emerge. From there multicellular organisms took up to a billion years to evolve. Animals in their more-or-less recognizable form (things like molluscs and sea cucumbers) appeared only about half a billion years ago. And evolutionary biologists have been observing evolution in our time for some decades. Decades. Think about it.

Here is a rough timeline in scale:

This idea is most likely because when evolutionists test evolution, they tend to seek more simple organisms like moths or other minute insects because changes for them occur at a fast speed. — Susu

True, we can watch bacteria evolve. I think that's because they're capable of such large populations. We can't watch the evolution of mammals except in our imaginations.

Have you read about the Caulerpa Taxifolia? Its a one-celled algae that can grow up to a foot long and it makes leaves and roots. Bizarre.