Empower Jace, compared to Amass, definitely gets better the more you have of it.
That may sound painfully obvious, but what I mean is while I'm perfectly happy with
Bothersome Noisemaker being my only
Amass enabler since there's actually advantages to the token staying small,
Empower Jace has to meet a threshold of 3 before you get real value.
In limited I think this will play out great, and as you can combine your various
Empower effects to reach 3 loyalty, draw a card (killing Jace) then
Empower Jace again to get a new token and surveil or maybe draw a second card that turn.
There's also the big haymaker loyalty abilities granted by cards like
Avatar of Burgeoning Echoes that while perfectly functional on their own, are a little 'on rails' so to speak without another way to speed up the clock.
Maybe with enough pushed cards like that (and the Enforcer Train mentioned) there's enough value running them just for a little bonus Surveil / draw here and there, but I'm afraid the mechanic isn't worth the hit to your complexity budget to warrant inclusion in a larger cube where it will be basically impossible to include at any critical mass.
Lastly regarding complexity, I don't think the mechanic is even that hard for new players to pick up / track. The bigger problem is that people will be naturally inclined to want to attack your Jace token (or hold back to creatures protect it), which I suspect that will almost always be a trap. Battles had a tendency to play out the same way, and as a cube designer I don't want to do anything that encourages people to direct damage anywhere but face. My games are going on for long enough already!