As I read whole topic, I think, I can add some from me. I am not playing SoD, all the ideas are for HotA.
I started playing Heroes 3, becouse I love this game. Why do I love it? For the strategy, fun and headache after playing many hours. Firstly I was watching some YouTube gameplays and started my PvP career, becouse I saw, some plays, moves, decisions can be done better.

For me as a player what can not be touched in this game is fun. That means all the randomness are good, but should influence game less. That means I disagree with removing TP/DD, but the value it brings, should be lower. Ideally, It should be possible for a player to win the game without control vs the player, who has control already. (Similar to the situation, when one player has mass slow and the other doesn't, many times it is still possible to do combat pretty nicely, but mass slow ofcourse helps, same should do control(TP/DD). Help, but not win by itself.

It's almost impossible to compete vs a player, who has TP/DD, when you don't have yours. That pushed game in one direction, to rush Mage Guild, get lucky with your choice, get control asap.
What I dislike with playing XL+U on hotA is that you feel, you're in a loterry. I understand, this feeling should be on JC, but not on XL+U. So my suggestion would be to weaken the control spells.
I like how the new Resistance works, it got changed, same I propose here.(less RNG, more human decision if take or not the resistance skill, it is only for a final fight, but only?)

We can think about many different options on how to reduce the usefulness of TP. I read the topic and the best ideas are to set a limit of total uses/day. What is impornat to think, is that early on this limit should be lower, than in a later phase of the game. Other problem with control are Heroes, who can use that. We cannot compare a normal way, standard way of getting control heroes vs making them with a help of magic uniwersity form Flux Town. So my suggestion on that one is to connect both problems and make one sulution.

Every Hero can have his own bar(which refreshes every turn, same as income, mana). Every hero starts with 1 point in this bar. For every 5 Levels, you get 1 extra point. So level 11 Labetha will have 3 points, lv 21 - 5 points.
For every use of TP/DD one point is spent. That means, that a new hero, with Wisdom/Earth/Air will have lv~10-15, what is 3-4 points. This hero is able to do 2xDD and 1x or 2xTP. So you have to be way more careful with your attacks, so you can move the Hero back. You have to plan your attacks by leaving Hero exackly in a Town, from which you want to attack(that way opp can catch you and kill). Sometimes more risk will be needed, but it's a risk you take, so that's more fun to play and watch, I think. Also, that stops the player, who gets control early in punishing his opponent. And later on, the control war should exist.

We are still able to use our control, control is still very important and strong, but it doesn't win the game by itself, I think. New Hero from Tavern with 25+ mana can use DD or TP, so we don't touch that. The only problem is getting a high level hero from Prison(lv 20-30). But on the other hand, most of the times they have crap in secondary skills, so you have to make a decision to keep them or not.
This move, I think will make players think about experience more, more strategy and planning will be done in order to win the game. Also, the adventage you get with Flux Town and Uniwercity is lowered, but still helpful.

This will slow the game down, but at the same time, it gives options for the second player, as he can still farm his heroes, map and look for control. Games will be longer, but ... I disagree that fast games are better(we have JC for that, on XL+U we should be looking for a relatively close, even, hard, interesting game).

With logistics and artifacts for mp, I think what should be changed are boots of speed. To easy to get, gives too much. Make it a major class art or even a Relic(who plays a homm3 knows, this artifact is really worth a relic class).

After we can think, if it's necessary to make TP/DD spell weaker(DD only in radius of 5x5 etc.)