I just looked over new 5th edition rules and the little part ive seen looks nifty.
https://roll20.net/compendium/dnd5e/Combat#content
They even have reactions mechanic in combat, which is very similar to my own ideas and dastardly plans. Those will handle all the attacks of opportunity and similar moves, in addition to the normal actions.
The whole system is made specifically for turn based combat, but it seems its taken the best from ToEE implementation and even improved on it.
Now you can move and attack, but you can combine movement and actions as you like - as long as the skills and attributes allow it. And even combine different ways of moving such as swimming or flying and attacking in between, if you want to.
You can go prone and even crawl while you are prone, at twice the cost of regular movement.
Enemy physical space is regulated nicely too, as size of bodies matters in logical ways and they even use that to clarify what and how can block a passage or a doorway.
The only thing that is not enhanced is initiative, which will be decided based solely by dexterity.
I dont see any reason why two attributes couldnt be used, appropriately for every class. So fighters should get initiative based on dexterity and constitution, while mages should use dexterity and intelligence.
And similar for other classes. Then just get some average or something.... it can be a very simple formula.
It seems more natural, reasonable and believable, while it would prevent dexterity being the best attribute - again, and give the usually dump attributes more use and value.
I can see some mechanics from DoS fitting very nicely in such a system.