I think the number of teams is unlikely to change, certainly in the short term.
The sole reason behind my comment is that the TV money is equally shared between the teams, so to add in 2 more teams, means less money for the remaining 12. It would equate to approx 250k per team per year, on the current deal that they would need to drop. Can you realistically see many (if any) of the existing club chairmen voting to increase the number of teams, whilst accepting reduced share of the TV money. I certainly cant see some clubs who rely solely on this money to keep them afloat from voting that one in.
Another factor would also be what Sky want to see and when. I am assuming that for their money, the SL clubs are contracted to have televised a number of games per season, with a probable caveat for Magic and play off series.
I am assuming Sky viewing figures are greater when Wigan, Saints, Leeds & Wire are on the box as opposed to say HKR,Wakey, London etc. I know that the 1st 4 teams mentioned will also appear more on Sky than the other teams, which has 2 impacts on clubs and fans; 1.reduction in no of spectators in the ground for televised games (match day revenue (ticket sales, programmes, food & drink etc and atmosphere) and 2. messing around with Thursday and Monday night fixtures, again match day revenues and atmosphere impacted.
So I suppose for the clubs, they need to work out the nett effect of playing in a TV game. Does the loss of match day income get covered by playing a TV match. If you are involved in 10-12 games on TV in a season, is there an impact to revenues or is it covered by the TV money. if that is the case, then surely a pro-rata allocation of the TV money would better suit the teams that are on the TV more