1..Smoke repair is doctrinal but heavy sappers are not. Still having super repairs and such tanks in one commander makes it OP. Chrchill will deal dmg to crew weapons, tanks etc. and will come back fighting before those units have a chance to replace lost squad members or repair their own tanks. Churchill will start dealing dmg again with max health too quickly pushing axis off WP too easly. You just can't kite it forever.
2. I already explained what should be done imo (4 options): these repairs should be much more expensive, or panther should get tungsten rounds (similar to jacksons), or give ost/okw a satchel charge (could be panzergrens with shrecks or okw panzershreck sturmpios to prevent crushing them and punish parking it in the middle of at units), or make it simply more expensive to reflect its actual performance.
We need to know what the repair speed of the units are. Some time ago, this was posted on reddit/transfered to the forum:
https://www.coh2.org/topic/50442/repair-rate-comparison-all-factions
I assume that every faction has 2 pioneers out, which is fairly standard for the mid to late game.
According to the Link, 2 fully upgraded+vetted Brit engineers could repair with a speed of 50; 2 upgraded OKW + OKW base with 49, Ost has 20,8. So Ost falls short.
(I never searched for repair speeds in the attribute editor before, please someone correct me if I'm reading the wrong values. But my values correspond to the stuff in the patch notes and Harolds numerical vet description mod, so it should be fine. Also this would mean that the Link is wrong, if there are no other modifiers. Please correct me if I'm wrong with the stuff below.)
UKF:
I find (for Brit engineers) the following values: 1. heal action 1,6; 2. heal action 0,5; 3. heal action 0,525
Which are 1. base repair; 2. vetted squad, 3. Heavy sapper upgrade.
-For a 5 man squad, this would lead to repair speeds of 8, 10,5 and 13,625, respectively.
The smoke repair ability has a repair speed of 11.
-> total speed of 13,625/squad; 27,25 for 2 squads + 11 ability repair = 38,25
OKW:
Pioneer repair speed: 2; vet2 bonus 0,75; upgrade bonus 0,5; combined vet+upgrade bonus (apparently there is one, I did not know this before) 0,1875.
-> Makes a total speed of 13,75 per squad, or 27,5 for two. Plus mechanized HQ repairs that I don't know about. Or approx 27 without the shady combined bonus.
I don't find anything about the base pioneers, so maybe they're the same?
OST: uses the soviet repair ability
repair speed: 1,6; vet2 conus: 1; (there's also an upgrade bonus of 0,3 for breakthrough package, but I'll leave it out due to doctrin)
-> Makes a total speed of 10,4/squad or 20,8 for two squads.
So OKW and UKF are pretty much tied, OST lacks behind
Repairing 5 pens (800HP) on the Churchill with 2 squads + ability would take 21s or 30s without ability plus time to drive back and forth.
Repairing 800 HP of the Panther would take 30 seconds for OKW and 39 for OST plus driving. Due to higher speed of the Panther it will gain some seconds as advantage.
Please keep in mind that in this setting, OKW has no Mechanized repair activated and Brits need to pay munitions, so there should be an advantage for them. Also everything is calculated for maximized repair speeds. And I assume that the charging Churchill does not take more damage than the defending Panther, an assumption that favors the Churchill.
I'd say OKW has no problem at all, since the time to get a Panther back to the frontline is pretty much equal to the Brit's Churchill. For OST, there's only a disparity if the Brit player uses the smoke repair ability.