I also love partisan tactics but the thing is that partisans cant cap so you are investing a lot of manpower to a squad/squads which can only flank and their effectivity is decided by the RNG
(random weapons). They are really far from being OP, but the thing is that you see them very rarely so german players have no idea how to deal with them and what are their disadvantages.
The second thing i want to comment on is the name calling in chat and the pay2win argument.
Basically they just acknowledged they were outplayed. I would completely ignore them and play the game as i like to play. No offence, but why would you ever apologize for using any strategy which is provided to you from developers. Even when TA was beyond OP there should be no apologizing for using it. Their lack of knowledge and the OP screaming after one game is telling a lot about your opponent. Probably immature kid who REALLY REALLY wants to win. just ignore these jerks.
The third thing is, look at the late game efectiveness of partisan doctrine and think for yourself, is it worth it in current meta? i will give you the answer, NOT AT ALL, you are going to need callin tanks or be very fortunate to get A LOT pshreck partisans which i am getting maybe once out of four.
last but not least, partisans + AOE weapon profiles(tanks, mines, etc) are just instasquad wipes because they love to hug each other more than any other squad.
So yeah, they are not OP
Relic Entertainment
cblanco ★ 
보드카 중대 
VonManteuffel 
Heartless Jäger 
