Speaking as a tiefling player myself. I'd rather keep the extra feat and skill points over gaining an additional level I'll likely never reach. Beside ECL races should be played for flair, not mechanical advantage. (Own personal opinion only here.)
It's one thing to talk about preventing advantages, it's another to address inherent disadvantages that make playing a subrace a masochistic endeavor. In my opinion, arguing a mechanical disadvantage as a blood price for RP that isn't even well-received her is not enough incentive to inspire me to make a character with an ECL. We aren't talking about a total revamp here, atleast I'm not. I'd rather just have an ECL subrace be considered his or her base mechanical level for the intents and purposes of leveling so that they may progress alongside their peers, even if they max out early on. In-fact, that might make them very appealing, because as you so frequently state: Most people do not make it to the level where the level 20 cap matters.
But, fewer people with ECL's make it to where level 10, even matters, because the road to progress for them is so ridiculously treacherous. Now, that isn't even a statement of being challenging, either. As an ECL 2 Subrace, unless you have been min-max'd and have someone else helping you find the best gear around, you are not, by server design, going to be suitable for most things you are able to kill. Only very rare, veteran-player exceptions exist because they have had such extensive experience with the server, they know how to game the system for maximized mechanical progression. This being said, I want you to think about the number of Tiefling and Drow PC's you have ever seen, and tell me how many of them have been male compared to female, as they are the two most common types of characters.
The only thing that those races really have going for them, is that they are 'Exotic looking,' which gives them an advantage in the sexual arena, rather than any other arena. So very frequently, that is the variation you see. Even more interesting, is that most people who are wanting to play a Drow, do not do so. They opt for a Half-Drow, because there is no benefit to RP'ing a hardline Drow here, and a Half-Drow does not have the same ECL as a Drow. They are, for all intents and purposes, equally as Exotic, with a more fulfilling body model that's generally considered more attractive, and as I've noted before, almost all the PC's from that bloodline I have met are female. They're female, because that's the only benefit you have in RP for the most part from those races is that it gives them an 'Exotic look.' Which doesn't work so well for men, but works in female favor substantially.
If you didn't want these things around the server, just get rid of those races. But don't go to bed at night thinking anyone for a moment isn't sacrificing half of their gameplay experience to play an unfulfilling line of roleplay, compared to practically anything else they could do on the server. They are giving it all up to try to shake it up, and being brutally and unforgivably punished for it mechanically, and only a few, few select few Tiefling/Drow/Etc PC's actually make it to end-game levels, a margin even smaller than normal PC's, and even then they are being punished for it.