I'll go through this line by line.
Sooo there will be a big change in textures with 1.5
You heard right. The whole setup of a texture packs' inside is changed. Not much different for the end-user, since you still have one .zip and place that in the same old "texturepacks" folder, just like everyone did since.. the beginning of time. Kinda. The inside, on the other hand, is a whole different story and indeed needs some work from the tex-artists' side.
i have heard somewhere that there is soem kind of mod that brings back the old system with one big file of textures, and not with multiple single ones.
Thing is, the
mechanism of Minecraft, when the program looks for a texture is going to change. It's not a choice the texture-pack creators had one fine day, but Mojang decided this. Apart of this, why (
yeah yeah, see below) would you want that? According to all sources I read about the change, its a change for the better, as mostly everyone seems to agree, that it helps to reduce the systemload MC has, due to this change. May it be minor, may it be major.. but afaik, the change is a good one, perfomance-wise.
Is this true? or is there even support for the old texture packs?
There
may be some texturepacks, which support the old style - but I seriously doubt this will continue for more than a few months at max. Why? Because the "old" system is only useful to MC version 1.4.7 and below. Which gets older. And older. And.. ancient. "MC Vanilla 1.6" is a silver light at the horizon by now, mod-authors are doing their last tweaks to their 1.5 versions, FTB is going to switch over from 1.4.7 to 1.5 sooner than later... in the end, its a useless effort. Take
any 1.4.7 texturepack and use that. Anything "newer"
a) will be for a minecraft-version, that utilizes the
new texture format
and
b) will be made for mods of a more recent version
ergo
c) you,
pretty much guaranteed, must use a new texture pack
It would be a lot of work to change my current texture pack to the new format...
Duh. Welcome to the club. Literally all texture-pack authors everywhere are fighting with the new system, are doing changes to their packs, have to rearrange their folders, have to understand who the f*uk a Jason is and what he's got to do with textures - whathavenot. All of this, while (FTB wise)
in the meantime keep up with mod-changes and their new textures.
And finally - no, I never heard of a mod that would revert this change. Again, it would be utterly useless for 99.9% of all minecrafters, being it just players, mod-authors or textureartists.