Honestly, the difference between CO and CoH were that CO you had only 1-2 attacks for single target(if two, usually one lighter ST attack with good dps and one bursty attack with more concentrated damage in one moment), and 1-2 attacks for AoE(often not much different types in terms of pressure damage or burst damage than STs, just AoE), while CoH you had 3-4 ST attacks and 2-3 AoEs.
Now, I agree that CoH's combat was "clunkier", I felt it had more depth because attacks always had secondary effects rather then just raw damage. Even fire had secondary "extra damage". Thing is in CO, powers almost never really have any useful secondary effects. Because of that, whenever one power becomes the new "best damage/second" half the community rushes to use it, because EVERYTHING ELSE SUCKS SINCE THERE IS NO POINT TO USE IT.
That is a core reason so many had switched to lead tempest and two gun mojo for example. Both do very high damage, but two gun has the best damage per second over time as a maintain and it's the best tier 0 power now with no competition in ranged. Blasts are currently weak(always have been), so they only get used by those who are forced to use em, archtypes. CO also suffers from the few secondary effects generally not being useful 90% of the time(the debuff effects that do exist are often way to low in magnitude).
CoH however made sure all the powers were "standardized", so that no one set was more powerful then another, and instead separated them on secondary effects, and those secondary effects made a huge difference. It worked, was just a hair clunky.
I'd say we could standardize attacks but set it up so that it's more streamlined, so yeah we don't need an "attack chain", but maybe say ranged and melee can both have combos in one power? And make secondary effects matter. I think that'd be better then both; we'd have the smoothness of CO but the depth of CoH.
Edit:
Thought i'd include how CO handled melee however before I forget. Melee sets in general in CO are generally far better in terms of viable variety than ranged. In the combos alone, many are very comparable in damage/second, but all of them are separated by secondary effects. Given the sets themselves are anything but "balanced", with some lacking AoEs entirely and generally being crippled for it, but they all have there advantages. Telekinesis for example has a superior crit chance with it's main combo, and that main combo rapidly builds up ego leeches, which in turn can power some other attacks to unleash a heavy burst that can then proceed to rapidly build ego leeches up again. You have the option of using the main combo for it's immense crit chance(and you can use it for either damage or more defensively), and bursting it out very smoothly. Other melee sets tend to do similar based on the buff/debuffs in play. The only set that fails currently is power armors laser sword, which has so much setup time and is so LUCK based in that setup time that it's totally useless.
It's not so much that laser sword itself sucks, but the fact that all of the new "laser sword" themed powers generally suck because you only have a % chance to gain the debuff effects and you essentially sacrifice alot of damage to combo anything together.