Actually, one small change. d12 needs to be fixed. Currently if the d1 hits, you can still block the d2. I don't think a single other string in the game can still be blocked once the first hit connects. And since it's negative on block, that means you will almost always be left negative for using d12 as pressure.
I honestly think the purpose of that string is to catch a counter poke from the opponent. Now I'm not saying that's the best option, considering we have a plethora of unsafe things to do in order to catch button presses but I feel it revolves around catching someone poking. Just remove it. I don't use it and all it does is tempt me and get me in unsafe habits against lesser opponents, which results in me getting blown up for it against competition.
F2 drives me nuts occasionally. It whiffs on a stand blocking Takeda because he is trying to look like Neo when he is stand blocking. It doesn't whiff all the time but I have to change my ranges in that matchup that I personally already struggle with. Call it lazy if you want. All the other inconsistencies with f2 are also worth of mention, as they already have been by previous posters.
In regards to the OP, I think Pumped Up is what you want him to be. He damages you more every time he touches you, especially in the corner where he gets up to 55% for one bar depending upon the starter. He also has the restand so at the very worst, you do a little bit of chip on top of that massive combo you just landed for some icing on the cake. 22% armored reversal isn't bad at all either.
Also in regards to honesty, yes, he is the most honest of the top characters. There are glaring holes that can be exploited but it takes a knowledgeable opponent to scout and take advantage of those holes. If you get to the point where you are able to press buttons against Jax for free, then you have fought the good fight and won (unless you catch 40% for getting greedy). I think people do what their intuition says and they don't challenge when in reality you SHOULD challenge. You have to know where the Jax is looking to armor or OH DP and go from there. If you block, you'll get chipped and tossed around the screen. Is it brutal pressure? Yeah. Is it Kobu level? No. All I know is I have background with Ermac and Jax feels more along those lines of honesty than most others. Please don't get me wrong though. Ermac is one of the most honest character in the game, if not the most and that's why he blows.
Necessary (not really because he doesn't need a damn thing in all honesty):
~ Fix f2 consistency
~ Ummmmmm....yeah
Quality of Life:
~ Map a new normal to f4 - f3 strongly outclasses f4 in my opinion
~ Make b2 able to be cancelled on block - I think it was previously mentioned, not sure
~ Make the command grab inputs more lenient for less damage or more damaging as is - as per previous post which is perfect solution in my opinion
~ D2 improvement - taking it a little far, trust me I know; more priority because as it stands you have to scout more than react; can't complain too much though because it hits behind his neck lol
~ Armored f2