That's the whole point of the nemesis system though.
The first, and this game, have three main driving points. The combat, the nemesis system and that you're able to slaughter endless hordes of orcs. The story in this game is sub-par at best, and it's fan-fiction and has absolutely nothing going for it compared to Tolkien's work.
If people don't enjoy the nemesis system, and the search for getting a great orc chieftain by your side with amazing traits, which the whole first game was about when the story was over, then I honestly don't know what else they expected.
And if they designed the nemesis system with microtransactions in mind, they sure did make a mistake by letting them get such a huge level boost. I exchanged whole my fort garrison in Nurnen, from level 30-ish orcs to level 50+ by doing this once for every orc. It took me 20-25 minutes to do it. I don't consider that tedious, and I had fun doing it as I enjoy collecting orcs and see what kind of traits they'll end up getting.