I played a bit of DWG1 and it's slow as fuck, considerably more slow than Dynasty Warriors 7. How about you stop bitching, play the game, learn some skills, level up some weapons, and then do your combo chains? It's not like you CAN'T do combo chains WITHOUT cancelling either. DWG3 is easy as hell in chaining combos. Get the Unicorn Gundam, set it to Unicorn mode, and you've got 50-100 hit combo right there without any effort.
Sounds to me you're just mad DW7 requires some manner of skill and you have to work for getting awesome, whereas, you're awesome off the bat in DWG3. And so, DWG3 is an outlier in Muosu games for me, in that other games, ESPECIALLY Warriors Orochi 2, you have to work your ass off to get beast characters.
You are taking these games like they're pure action games, when you should be embracing them like they're rpgs, since they have similar character progression.