I see the argument that MP shouldn't be tied to SP story. That I don't really agree with but at the same time I do feel like there should be a way around being forced to participate in a game mode that you don't enjoy. Solution would be that certain war assets like materials to improve ships, vehicles, weapons, etc, credits and other in game materials be awarded in MP that transfers to single player. SP player only people should still be able to get these materials and resources through routine exploration, mining, side quests, etc. This allows everyone a playstyle that suits them.
Bioware could also have something like the verbal news feed reflecting their progress in MP as well. Like Alliance forces captured a base on whatever planet, etc.
This way both sides are happy.
How about having people who only want to play the MP and not the SP, that they, the MP crowd, should they be forced to play a SP campaign of lets say at the fastest can beaten in about 40 hours, that they have zero interest in playing multiple times to get all the character classes, weapons, armor, mods, gear, maps, credits, and etc to make the MP more fun and all the MP DLC is at store that can only be accessed about 30 hours into the SP.
Does that sound like fun to you?
I'm not exactly a big fan of MP in general but that doesn't sound to me. I'm sorry IMHO forcing players that don't want to play in either mode that have no interest in the other to get any benefits no matter big or small is bad idea, and would do little or nothing to make people who don't enjoy that mode enjoy it. A lot of time that I played the ME3 MP felt more like a chore (and that is even more in the few times I ventured into the DA:I MP) than fun and the whole thing got old after awhile.