I agree that 2wt's and lighter can be super fun and good fishing tools as well.

The only thing I don't care for when it comes to fishing rods lighter than 3wt (and this is a generalization as far as 3wt being the cutoff point), is losing some ability to lead big fish away from cover when you need to fight a larger fish in a small area.
- I've heard all the arguments on this, how someone can horse a huge fish just as well with a fourple zero weight as with an 8wt, cuz it's all about the breaking strength of the tippet.....
- But when you have a very limited area in which to fight your fish in order to keep it from diving into a log jam or under a root wad, and you need to use the butt strength of the rod to lead the fish away from the structure, while the tip of the rod is really bent while applying pressure from different angles....this is where the super light line weights that I have fished just don't get it done

I admit that if there is more room to fight the fish, that an angler can apply just as much pressure with an ultralight fly rod...but not when the circumstances dictate that your rod is seriously bent and you still need immediate butt strength in order to keep from losing your fish in a very small area. Anyone who has gotten into some big post spawn cutthroat or rainbows on a small Rocky Mountain headwater, or a big pre-spawn brown on some creek knows what I'm talking about.

But I digress....ultralight fly rods are so much fun and so "fluid" to fish!

Happy Trails!