There is tedium built into every gaming achievement. The only commodity a gamer has to offer is time. The fact that it does take time/effort is part of what separates an average player, from the more dedicated one. Getting "Raid Gear" in other games = tedium.
Now, that unlocking Engineers involves a time wall is not inherently a bad thing. Acknowledging that the effort for each engineer is not Hard, certainly is a rebut to the OP's issues. It may take time, as it should, but it isn't hard to do, sounds like a reasonable recipe for a game mechanic.
Wasn't always the case. Games used to be fun.