Point 1 - These are not the regulations of the RFU, they are of the PGB, of which Championship clubs are a part, and indeed I believe London Welsh actually voted for the current regulations. The RFU is guilty of enough sins without blaming them for those of which they are not totally responsible.
They aren't.
Balls to the off feild stuff, rugby is played on the pitch and on the pitch London Welsh are actually a better side than Exeter were when they came up. Hypothetically if LW have their stadium in order and the RFU let them come up I'm fairly sure they wont be the whipping boys as arrogantly stated before by Howzy
The season Exeter went up they finished the season 26 points clear of London Welsh. The season before 28 points. The season before that by 46 points. London Welsh finished 14 points off the 1st spot this season and 14 points off 2nd the season before (Wuss were so far clear that there's no point comparing).
I fail to see any evidence there to suggest London Welsh are a better team than Exeter or other teams that have gone up. On the contrary, I see a great deal of evidence that says they are doing worse. Also, while I can't vow to it, it appears that Exeter didn't use any loan players that would need replacing in their promotion charge. Finally, Exeter have brought in players to strengthen the squad - not always with great effect, but they've played a part, and I don't think they'd be in the HEC without Mieres.
Now, Exeter, with an average crowd of over 8,000, no rent to pay and the supplementary income from owning their own stadium, can't/don't wish to afford to strengthen their squad up to the wage cap. How are London Welsh, with an average crowd of just over 1,000, rent to pay and no such complementary income meant to find the money to seriously strengthen their squad? I don't know what London Welsh's turnover is - although I am led to believe they already operate at a loss - but suspect it falls short of the 7.4m that is the rough average figure for turnover amongst the Premiership clubs outside the top 4 (would be higher with them included). So unless LW have a LOT of backing from somewhere, I suspect they will be a way under the wage cap.
Looking at the objective stats, there is strong reason imo to believe London Welsh may well struggle next season.