I played the leaked beta, some pretty cool stuff, but alot of it was still unfinished
2 new heros. Batrider and Tauren Chieftain. Batrider had some kind of shackle / vortex mix ultimate and could fly over things, but not working properly. TC only had ulti, which was a stomp and gave you fatal error, so i dont think hell be like that in the final version

New items: Combination of the magic stick and 3 branches (costs 200). Same effect but 1 itemslot instead of 4. Could be worth it very early in the game, but not sure if its worth the gold.
Force stick: The effect of the axe of the secret quest last version, pushes an opponent in the direction he is currently facing (something like 800 or 1000 range). You can use it on allies and enemies afaik, so it would be imba to safe people or throw people into gangs.
Remade heros: Viper got a buff (i would say). Instead of fury a passive skill that gives you attack bonus similiar to huskars passive, but on the enemy. The less hp your last attacked enemy had, the higher the bonus. So if your enemy is at 1%, you can get up to 120 bonus damage, if its at full hp you get 0. It gets charged up like tidebringer, so you can lasthit, charge it and then harras with the damage you get added. Basically lasthit

harras

lasthit

harras which seems perfect for viper.
Razor got fury taken out and replaced by the old lightning storm, but changed. It works like storm pandas old passive, charges up every X attacks, and then aoes around the attack, but without purge.
New ultimate is a speed bonus (10 / 20 / 30 %), but the more opponents are around you, the less bonus you get. So its bad in creep masses, but strong for chasing sole heros.
Beastmaster gets a new skill, which is like trolls fervor, 40% ias aura, instead of his charging up IAS thing.
Troll gets beastmasters old skill, getting faster with each attack, up to 100% bonus.
Lina got Ultimate (the spell, not her ultimate) reworked. She gets movespeed and attack bonus for each spell she casts over a time (passive). It lasts 6 seconds and the bonuses ofc stack.