Regarding the TvP thing, I think for the most part it's balanced. Terran do have a good early game advantage though thanks to the strength of the marauder and conc shell. Once stim and medivacs come into play Terran also are an omnipresent threat anywhere on the map.
Once protoss gets access to templar tech they have a small advantage.
The major problem PvT from the protoss side, is that they are extremely limited early game until warpgates and some sort of aoe. This gives Terran the ability to reach the mid game with an economic advantage.
If Protoss enter the mid game on even terms then usually they are in good shape for the remainder of the game. The power of templar tech somewhat mitigate dby the power of marauders and medivacs.
The other strength Terran have is the availability of a number of openings that require different counters from Protoss. This isn't so much a 'balance' issue, as a game design one. Just as Zerg can counter anything Terran throw at them, there exists the requirement to _know_ what is coming.
Protoss at least have observers. But they wont catch for example, the increasingly common 5-6 rax marine rush or the ever obnoxious fast 2 marauder 4 marine 2 scv rush.
Terran have a lot of flexibility in the early game which sets them up for the rest of the match. In PvT it's the marauder and conc shell early that's the most brutal thing tbh. Late game the way marauders and stim own buildings, is bad too. I think it's worth exchanging some sort of late game protoss nerf (templar cost to 200 gas or something) for a early game conc shell and armoured damage nerf to the 'rauder.
I think, also, repeating what I said before, making access to dt tech cheaper/faster might give protoss a weapon to 'keep the (terran) ******** honest'. I.e. if Terran blindly go 5-6 rax all in and protoss go fast dt, T should get owned. It would add a little more dynamicism to PvP (counter the now default 3 gate robo colossus vomit) and PvT play. Sadly this would break PvZ even more than it probably already is, as PvZ is becoming even more rude to the Z than ZvT if the GSL is anything to go by.
But no one plays Z anymore really so they might as well just focus on PvT balance
