HGB has a range of 12 and can keep vehicles immobile for a very long duration.
I don't know the exact range of a satchel. 10? But it's about that, there is no huge difference.
You should not use the Penal as the benchmark because their are badly designed.
You also seem to underestimate the long immobilization effects and possibility of "stun lock" especially if the weapon becomes homing.
Finally have even less reason to compare it to Penal because my suggestion is either to be moved to Ro.E. or to become a homing "soft snare" for IS.
I compared the HGB to Penal satchel as they are basically the same abilities. The satchel ability is not OP, so unless the HGB synergizes extremely well with IS or any of their abilities, there will be no problem (I already addressed the smoke twice).
Also I am talking about the HGB in it's current implementation, which should be clear from my post. Please read it carefully, I never suggested that it should be a homing snare with stun lock and everything. 
The HGB is basically a normal satchel. Make it a normal satchel then. No stun, just engine damage. If you get stunned/snared by a normal satchel, you very well deserved that because you did not react to the squad closing in, the whole duration of the throwing animation and a >3 seconds fuse.
Penal do not have access to smoke or to HE grenades.
I have stated thrice now that I do not think it will become a huge issue for multiple reasons. You have not addressed anything of this apart from repeating that they can be used together with smoke.
Imo patch team (Relic and MOD) have spend too much time fixing the "important" things (and then having to fix them again and again) and far less fixing smaller thing that could improve the game allot and are "easy" and "safe" fixes.
The change is simple and easy. Simply revert AOE damage changes, keep the munition reduction make the weapon homing and remove the affect that make the vehicles immobile or move its Ro.E and remove the immobilization. 
Yes I just completely disagree on that. Balance team should fix the glaring issues and not spent their limited time on minor things unless they are very easy and unlikely to cause issues.
What you are suggesting here is
1. A complete rework of the ability
2. followed up by a change of the unit that has access to it
This is not an easy thing to do and requires a lot of time and testing for honestly little gain. Nothing about is "simple and easy". What makes you so sure about your idea not having to be fixed "again and again" (which is an overexaggeration, many things have been quite fine after the first patch and potentially a small hotfix) as well?