I honestly don't know what weapon models you're looking at -- most of the Slipgate weapons look a lot like their original versions, with some artistic liberties taken on them. Our Slipgate rocket launcher, for example, is simply more rounded than the one in Quake 1. Nothing is spot-on, of course, but they're all very recognizable.
The exceptions? First, the axe. The model in .99f will be replaced in 1.0, and you can see the model that will be there in the gallery.
Second, the shotguns. Once again, the models in .99f will be replaced in 1.0. Again, you can see these in the gallery.
Third, the Shaft. You're right, this one doesn't really look like the Q1 Thunderbolt... I'm personally hoping it gets replaced with a model that looks more like the brown bolt thrower from Q1, with an "open housing" like the Doom plasma rifle... but that's my opinion. I don't make the models.
As for animations, they're being worked on. Slipgate's weapon animations are the simplest out of all the classes that need this work done, but that doesn't mean it's an easy process. It takes time to get them "perfect," and we have no plans of releasing anything but what we see as perfection when 1.0 comes around.
As for the "Slipgate class should be the best one," that's an opinion, and I'm not going to go there..
Er, anyway. The aim is to have the classes accurate to the original games, but on a level playing field. In this realm, Slipgate is
very similar to Quake 1. Keep in mind that Quake 1 didn't have things mortar shells, Doom plasma, and Q2 rails flying around. The Slipgate class itself is fine -- it's his environment that makes it seem different. The only issue with Slipgate right now is his jumping, but that will also be fixed in 1.0.