Don't get me wrong, i like the fact that a logi is different from a scout or a commando is different from an assault but too much differences give balance problems.

So, in my opinion the two extreme ways of specialization, scout & heavy are too far from the rest of the suits.
Here is a little grafic:
s= scout
l= logi
a= assault
c= commando
h=sentinels



Scouts: they have to much EW and HP regen, except min which is probably the most balanced and it's the best example of how scouts should be, without bonus on EW the advantage is only related to your slots and to your fittings, if you want to EW you have to renounce to something else.
In Hotfix charlie scouts are moving another step in OPness, 3 of them will get a EW related bonus and even if the numbers will balance them within their class, they are unbalanced vs other classes.

Sentinels: I don't know if the problem are HP or resistances, one of the two should go, or maybe a little nerf to both, add the fact that heavies can use the most powerful weapon in the game(HMG if you don't know), this make them really unbalnced with other classes.
I would add another heavy class and move commando to medium frame tier, let's call the new heavy berserk, basically something between commando and current sentinel, can wield heavy weapons, but have less HP than sentinels and current sentinel mobilty.
Sentinels would keep their HP and resistance but have less mobilty.

Commando: they are fairly balanced with logi and assaults now, but with the new assaults in hotfix charlie, i would give them a little more mobility, they have a very little slot count, logi/assaults can tank the same amount of HP and have some utility mod.
Have a second light weapon is good, but it cost: a grenade slot, some H and L slots, a larger hitbox, overall agility, meanwhile you gain a little more HP.
Imo commando should be an assault with a second light weapon, the third class of medium suits.

Logi & Assault: they are the middle suit, good for everything, logi is specialized in equipments, assault in weaponry.
All the balance should start with these 2 class (i would add a 3rd, commando should be a medium frame tier).

The solutions are different, you can increase the difference between classes, or reduce it.
I would like to reduce the differences, but keep specializations.