The question really is would you prefer having a potentially unbalanced game or no game at all. For people in the less active timezones, the former would likely be preferable to most people. Being from a less active timezone, I am very much against reducing the search range without any recourse. A reasonable middle-ground solution would be to implement a checkmark that asks "Would you like to increase your search range? It will increase your chance of getting a game but also increase the chance of getting an unbalanced game." that the user can tick or untick. If you tick it, you get reduced search range (e.g. +/- 300, or whatever is reasonable), and if you untick it, the search range can increase as it currently does in TMM.
This option should also apply to ladder 1v1, allowing your search range to increase until you find a game. The rating system should be able to handle the "imbalanced" matchups that result (e.g. if I face a 1400 as a 1900 on ladder, I would have a 95% chance to win, but get like 2 points or something from winning, -14 from drawing, and -30 from losing).
Also, from my anecdotal experience, I've personally been in quite a few games with a weaker teammate against 2 ~1500 opponents and come out victorious. I think it's very reasonable for a 1700+1000 to beat a 1400+1300, with the outcome probably being 50/50, if everyone is actually at their rating (separate issue). This is a little beside the point, but Swkoll showed me a replay the other day where his 800 global/700 ladder/700TMM teammate just crushed Inspektor_Kot and Wesh, who are both rated around 1.8k. It was very entertaining to watch.