I've been thinking about this for about two days now and actually don't think it is a good idea. Well, not right now. Here's why:
Not a lot of people will be using it.
It would be a lot of work for most people to download the resource pack and turn it back on/off every time they join/leave RoF. Now of course you might be like: server-side resource packs! They added that some time ago! When you join RoF you'll get a message to download & enable the resource pack! Simple! Wouldn't that work?
Nope. It wouldn't. Why, you ask? Well, remember PTNT? It also had a custom texture pack. I'd always join it and use the texture pack, just 'cause it looked pretty. The problem? If I'd use /logout, get kicked or banned (not that the last two ever happened, but I'm pretty sure it would also happen then) I'd still have the resource pack on, in the lobby and on other servers.
Not a lot of people want to use it.
And of course you've got the problem with it being a custom resource pack, which has the problem that not all people will like it. For example, I know a lot of people like this "sphax purebd" resource pack (or whatever it's called) and it still remains one of the most popular resource packs. But I dislike it. Sure, we could make our own resource pack, and it could look pretty, but what if over half of the players don't like the way it looks?
And another like 40% don't use it because of the first reason I've given? Welp, then you don't get a lot of people using it. But I think what I'm going to say now might just work actually:
Make some minor edits to the vanilla resource packs. I wouldn't even go as far as changing block or item textures, but just a few things that could enhance the player's experience. At the moment I'm suggesting two different resource packs (with the new 1.7 update, people can just select one of them if they only want to use one, and both if they like both):
No pumpkin blur
Pumpkins are quite important in RoF actually, especially the (can I still call it new?) Pumpkin of Loden. Hell, I wear it all the time if I don't forget to buy one, it's more important than a helmet to me and only costs like 15 cookies. But a lot of people don't wear it a lot, unless they really, really have to, because wearing makes them almost completely blind.
I don't have this problem. Why? Well, I made myself a quick little resource pack which just gets rid of the pumpkin blur and gives you the ability to see clearly while having a pumpkin on. Why not make a resource pack for that, put it on the forums and have maybe a few people use that?
No popping lava sound
You all know that popping sound lava makes these days (they added it in 1.2 or something? I dunno.) which is, of course, a nice addition to the game, but here's the thing: For a lot of people it's annoying, or even laggy. And no, don't be like: "I don't have this problem so it's non-existent and nothing should be done to fix it." Don't be like that. I know it's a problem and a resource pack that makes that sound a lot quieter or even non-existent (if that's possible anyway, probably is with the 1.7 update) would be quite excellent. Alright, you might be able to turn it down/off in 1.7 with the new sound settings (it's probably under "Environment) but that also mutes all of the other environment sounds and this would be a better solution.
tl;dr Yes, this idea is nice, but not a lot of people would use it or want to use it as they just don't like the custom textures. I personally think there should be a few resource packs, each with their own minor edits: One that removes the pumpkin blur, one that removed the popping lava sound, and maybe, just maybe one that re-textures some blocks/items to look a little lavay.
But nothing major. And definitely no "forced" server-side resource packs.
