I appreciate that the mod is only alpha, that this is a pre-release, and that things are liable to change, but that's a good time to give constructive feedback.
DO SOMETHING ABOUT THAT RAIN MODEL
Please.
I've just hacked a r_normqrain cvar into my engine to enable me to disable it.
Suggestions: Replace it with particles. OK, most engines impose a hard limit on particles, but that's easy to overcome (hell, I posted a tutorial on it here, there's no excuse), they're faster to render, and you can replace each big batch of verts with a single particle quad. This can result in a potential 4x or more speedup in rendering the rain, meaning that you can add even more cool stuff to slow it back down again.

If that's not acceptable then reduce the texture size. It's not even funny. For starters it's HUGE, and secondly it's a non-power-of-2 size. There is no excuse in this day for having any texture with a non-power-of-2 size in a mod (some external texture packs suffer from this too). Most hardware accelerated engines normally can't cope with such textures and must resample them, normally up. That's a 2048x64 texture, which is starting to push on the limits of some cards. Multiply it by the number of skins in the model (6) and we're just being silly.
Given the amount of detail that actually is in the image, I'd suggest that no more than 256x64 should be enough. What this will mean is that the engine and GPU don't have to waste muscle on squeezing a huge texture into a tiny space, meaning yet more headroom available for cool stuff.
OK, I appreciate that you're a mapper/modder first of all, and that finer details of what can and can't work engine-wise may not be your thing, but here's a chance for mappers/modders and engine coders to do some work together that will result in a better end result all round.

Seriously though, it's a cool mod, and what I've seen on the QExpo pages indicates even better is on the way, and it would be sad if something like this - especially something that could be so atmospheric in medieval maps - ended up ruining it.