Oddly, I would be MORE interested in DAMP if it were integrated into the SP campaign. Mission completes that opened up new perks for the Inquisition or story/areas to explore, for example. That's how BioWare might win over this particular, overwhelmingly SP-focused gamer.
But as described, I can't say I see any real point. Even my fun needs a purpose (that is my issue, I'm aware).
No, that is a completely wrong way to go with MP. People who bought a mostly SP game should not be punished if they don't play the MP aspect. I would be totally irate if this was the case and I was losing out on content from the SP campaign. This also would affect those without the means to play online with others.
I think Bioware learned a good lesson from ME, you can't force people to play part of the game they don't want to and expect them to be happy about it. Locking any content from SP in an attempt to give rewards to those who play MP is a terrible idea. I like the two play modes being as separate as possible, thank you.