I think its just their mobility in general. The ability to react to someone capping a point gives eldar a huge advantage, transports or not. The gravtank roadkill i dont particularly see as a major issue, as games are won in buildings/points etc. Killing 1-5 people a match by running them over isnt game breaking, more annoying. Eldar win more because each aspect is clearly ment for a specific role. Something a team of LSM struggle with because of the overabundance of choices when it comes to weapons. The fact that the starting weapons hold up rather well helps a crap load with very few mod options.