My view (for what it's worth!) is that gazing into the crystal ball - whilst looking over the shoulder, the following scenario pans out...
Sheffield Eagles merge with Doncaster RLFC to create a Superleague club Don Valley Eagles (or whatever).
Year one all goes well, however there is now a wealth of talent in Sheffield and Doncaster, as both clubs had excellent links into schools and clubs prior to the merger, now not all those kids can benefit from the Don Valley Eagles' plans. Therefore kids don't get the same opportunities, there are a number of players who are good enough to play Championship or Championship 1, but no where to play it. What happens?
The new Sheffield Eagles 2015 forms, from nothing, with a team of volunteers spearheading the revival. Borrowing kits from Lancashire based clubs to prevent clashes, playing out of Don Valley Stadium, starting at the bottom with no team in place for the start of the season, they manage to survive and the look to build on this to create a force in the Sheffield area once again.
All of a sudden, the SL club forgets about the Eagles, and becomes Don Valley Giants. The new Sheffield Eagles 2015 club has a loyal following of hardened supporters who've been with them for years.
All sounds a little too familiar for me!!