Oh hello. I didn't see this post last week.
A lot of these ideas are intriguing though I'm not sure if I would want to devote the coding effort and time to test the mechanic changes on a map where basically 4ish people play every weekend. =P If I did do any coding effort, it would be to remove the last hit mechanic because it's pretty terrible in a map that does encourage players to team up with each other. And yeah AoE is just too good.
Workers pulling waves is a pretty reasonable demand (would probably give hired workers just 1 HP to achieve that =P) though it seems like a hassle to make a trigger for the worker not at a gold mine yet.
On sieging, those changes would be pretty drastic so I'm not too inclined to do them since there are other factors involved with them. Like you said, teleporting would have to be tweaked a lot.
Fun fact, I was considering such an item when I was trying to tweak Flo (even gave her a talent that basically does what you're suggesting). Melee heroes really get the brunt end of the stick with WC3's terribad pathing.
Consumable Suggestions: Yeah they probably should be buffed, though I don't really know how to tweak them so much since I almost never use them.
Obelisk/Digmaster buff: Interesting though I dunno if I would want to code that up. Digmaster rage could be potentially abusable by heroes who can heal, though it often doesn't work out so well since units tend to focus on the Digmaster more so than a tower.
Gen restriction: Seems iffy as it can make you pull your hair out at teammates that put gens however they like. Also this doesn't sound easy to implement with the way the gens work in EotA.