As a player i have wittnessed that pc's do NOT want to be challenged to battle since there is no credits to be won if they win.I think in the best intrest of everyone if you change all the missions that want you to challenge other players to something else,maybe more npc challenges or 2v2 battles.It would help us players to finish these missions.
2v2? No way! There are enough problem's with 2v2 (unfair matches, noob partners, trolls...) without making more missions forcing us to 2v2. Challenges are significantly easier than 2v2 matches.