I never used those and ran a stealth kit. The game allowed for any playstyle to be viable.
Because it's more fun to feel powerful then subdued. The other titans need to be brought up to feel fun. Right now they are weak.
If they are all balanced well, how do they feel weak? They only feel weak in comparison to Tone and, to a lesser extent, Legion. They don't feel weak in a vacuum. You're asking them to change the balance of a ton of stuff and the game overall. If they tweak every other titan up to Tone, congrats they'll all feel equal, but chances are something else will be broken by all that tweaking and the overall game will feel different as it will bleed over into interactions with the boosts, pilot vs. titan battles, etc. If they tweak only Tone, congrats they'll all feel equal and nothing else will be affected.
For a very plain example, if there's a game where most guns kill in 6-8 bullets, but one gun kills in 2, the solution is not to make all guns kill in 2 bullets. That's making an entirely new game because then everything is dead near instantly instead of having a higher TTK. The solution is to bring up the number of bullets that gun requires for a kill in line with the rest.