You shouldn't be judging the faction on its commanders. You should judge it on its core as it is present every game in every mode. Commanders are a separate issue that should be addressed individually. Faction balance has nothing to do with them.
Commander have a lot to do with faction design since they influence the performance of core units directly or fill blank spots in core roster. So they have to be looked at when you are balancing the core game.
Take the UKF Emplacement commander for instance. It directly influences the performance of emplacements and makes core emplacements hard to balance as a result. There are multiple examples of commanders that give abilities or additional weapons to core units.
If we have a look at the two mentioned commanders:
Mechanized Support Tactics
Guards
AT-Gun Ambush
Mark Vehicle
IL2-Precision Strike
ISU-152
-> Fills spot of elite infantry and super heavy AI unit. In addition you get a passive ability and two very good munition depended abilities, which give soviet a way to spend their munition in another way than spamming mines. Great designed commander which influences the core of how soviet is played.
Royal Artillery Regiment
Early Warning
Concentration Barrage
Valentine
Sexton
Perimeter Overwatch
-> Good abilities on first glance but a horrible designed commander in the whole. Why? Valentine comes far too late in 3vs3 and 4vs4 to have a real combat value other than calling down the Concentration Barrage for munition. But even more disturbing is the fact that pretty all commander abilities are munition depended (including Valentine somehow) while UKF is pretty low on munition generally (IS upgrades + Brens + grenades/mines + heavy sappers and so on...). There you have a further context between balance of core design and commander design.
So while Mechanized Support Tactics adds a lot of interesting doctrinal stuff that can be used and removes some blank spots, Royal Artillery Regiment is solely about indirect fire in such a bad overburdened design that you can never use all the commander abilities to full effect.