I agree with ubersaurus - the time of day thing was pretty neat. I think they should make the time of day / night alternate with play time, however, and not with the actual time of day in the real world.
Re: the huge amounts of Pokemon
Many of the new Pokemon added in Ruby / Sapphire were necessary to fill out the ranks of the Steel and Dark types, which were introduced in GSC and not fully utilized. It seems that they're trying to create a lot of different mixes & matches of types, even covering some of the more obscure ones (i.e. - Jumpluff as a grass / flying type). This really does add to the game, as it can make for some intriguing strategic challenges if somebody makes a team with some of these oddballs.
In addition, the Steel, Ice, and Rock legendaries from Ruby / Sapphire were a welcome change from the Electric / Ice / Fire legendaries from RBY / GSC.
And re: this whole thread -
It sounds like most, if not all of you have never played Colosseum. That game took the rules of Pokemon and "twisted" them a little, having you "snag" or steal other trainers' Pokemon, having Shadow Pokemon, and having all battles be 2v2. That game certainly kept the formula "fresh" and avoided a lot of the stale-ness that the original poster was talking about. Give it a try!