I don't know how complex modding is.....

So I'm curious - will it have to wait for the GECK for people to mod less ammo/chems/stimpacks/food/fusion cores etc. so that survival is harder due to resources not bullet-sponges (I prefer normal with mods that make resources scarce)?

I saw a basic less loot mod on Nexus but it didn't seem to affect a lot of the items I hope to be lessened (ammo/stimpacks/fusion cores and no healing food/water)..... also looking forward to a basic needs: eat/water/sleep.

Just wondering if I should hope and check for it now or wait until GECK?

Wait for Geck.

EVEN if someone did make those kind of mods, they would likely break the game, as they were probably made with TES5snip, which was a pre-creation kit program made for skyrim based on what was known about Oblivion, but it turned out, a lot of things changed, so the program only kind of sort of works and mods made with it tend to break save games.