The Current Balance State of Rageblade, Not The Champions
Ok let's look at the stats this gives..
AD +30 AP +40
Stacks grant +8% attack speed, +3 attack damage and +4 ability power for 5 seconds, stacking up to 8 times, granting a total of +64% attack speed, +24 attack damage and +32 ability power.
Total AD with 8 Stacks= +54 Total AP with 8 Stacks= +72
Basic attacks deal +20 (+ 15% bonus AD) (+ 7.5% AP) bonus on-hit magic damage to the target and nearby units in an area of effect.
So with the Rageblade alone with no items grants you +20(+8.1)(+5.4)= a total of +33.5 on hit damage.
Personally, I believe the flat stats it grants & the numbers stacking up needs a nerf. The on hit damage numbers seem to be in a pretty poor spot as well, but that is because of the numbers this item gives it alone. I believe they should focus on making it as a late game scaling item that is a really poor to rush item in the early game & even then as a late game item the on hit wouldn't be as insane as it is currently.
Riot just nerf the Flat Stats and the Scaling Stats on the stacks. This item is in a really poor spot right now when it comes to balance. We see devourer champions abusing this item way too often such as Master Yi and mostly Jax. I'm putting my concern out there as a Jax main, I want the game to be fair for everyone and Jax was in a pretty good spot until this got a masive buff. Plus the ban/pick rate of Jax is absurd at the moment, which for us Jax players makes us turn to other champion picks.
If you decide to nerf the champion it would not do too much since rageblade is abused by so many different champions right now. Just way too unfair to the game right now and makes it anti fun even for me to play as Jax.
With Deepest Concerns,
Dunk Master Jax

or
, but don't worry, unless you run into them, you will slaughter everything on your path. And don't even start by telling me that all these champions are hybrids. They are not. They have mixed damages (not Yi though) and a couple of AP scaling so that they get a little more power with Nashor, but that's it.
with
and
it is some of the most broken stuff i have seen
yet.