some buffs to the exisiting hybrid-items would already help, and better hybrid ratios for champs would be needed.
We only have 3 hyybrid champs left, Akali, Jax and Kayle.
I think one bug problem for hybris champs is that they can't itemize for hybrid pen, which hurts their lategame a lot unless they have redicouls scalings(which makes them rather snowbally and usually massive at midgame if the get a lead)
Also, hybrid builts lack a multiplicative stat going for them in the late. AD+AS is already multiplickative and can scale even further with crit and crit damage, ap get's increased by 30% from deathcap.
Hybrid champs would need something like akalies passive that alows AD to increase the effeckt of AP, and the other way around(akalie does % of her total AD as bonus magic damage. The AD scaling depends on ur AP, AD and AP scale multiplicativly with each other)
We also lack a bit hybrid items without AS.
Gunblade is the only item for champions that scale of AD and AP, but not AS.
The problem is that balancing hybrid champs is rather comblicated, as their mixed damage makes the pretty strong early and midgame, and it's also hard to get numbers right so a pure AD or pure AP does not outclass hybrid
Another problem for hybrid(and ap-onhit) builts is sustain. We have Gunblade, but alot damage from hybrid(or magic-onhit) champs comes from on-hit effeckts, which often don'T work with spellvamp.
If simply all on-hits would work with spellvamp, it would already help alot.
I'd also like to see a buff on trinitys ap to make it better for hybrid. It currently gains 10ad(360g), but only 5 ap(109g) from the combine. Increaseing the ap from 30-40 would already help alot without having to much impact on ad-champs.
p.s, if Ruind king is better on a hybrid-champ like jax than a hybrid item, then either Guinsoos and Gunblade need a buff, or BotrK a nerf(probably a combination of both)