The times when I've had ASFs try and ram me is when they are hell bent on getting their Thunderbolt shot on me, but I maneuver my mech toward them and under them, thus forcing them to angle a steeper and steeper dive. By the time they manage to get the shot on me, there is no pulling up from the dive and they kamikaze.
To me, that is a stupid behavior that should not be rewarded. Of course, my mentality in MWLL is to try and never die during a match, thus taking a realistic approach to the game play. It is very rewarding to go 0 deaths in a game and I sympathize with ASF pilots that landing is suicidal.
However, this is still a game, and this is just one way to play. Another way to play is to be a suicidal maniac in every possible iteration of the phrase. This can be kamikaze pilots, charging demolishers, vulture Bs who charge in and kill kill kill then die, BA that spawn from APCs and just meat grinder against the enemy forces over and over again until their APC is destroyed, then they start it all over again by buying a new one.
The meat of this debate is that the mechanics need to change so that such behavior is not optimal. In the case of ASFs not dying when they ram another plane, that is surely an issue. As for realism vs. gameplay, however, I would suggest that in order to stop the kamikaze behavior against mechs, that ASFs should never damage ground units by ramming them. The ASF should explode, but inflict no damage to the ground asset. If the kamikaze behavior does inflict damage, then it is as if the game encourages players to do so by rewarding them with kills.