How often does that happen? And how long do they keep the gear down? I would think every airline's procedures involve raising the gear as soon as positive climb is established, if you were to lose an engine you really don't need the extra drag.
The only reason to keep it down a few seconds longer might be to cool the brakes, but highly unlikely.
If we have an emergency we are likely to raise the gear before doing our circuit and if its just a gear problem, say we can't get the gear up, well that is not really an emergency is it? We would take our time, decide whether to return or divert to somewhere else, and anyway, if we did decide to return its not going to stuff up your arrival. And you can still send your departure off, we should still be going forward and upward in the normal manner. And if we do have an engine failure we are likely to be making an emergency call and going straight ahead, so you can call your recently departed aircraft and turn them away from us, should the SID also require them to go straight ahead.
And how often do you get an emergency call at that stage, with an aircraft with its gear down longer than normal?
In fact, I don't really understand your problem!