While 'TC' has become the common denominator for The 3rd, Falcom described it as 'Sora no Kiseki Advanced Chapter'. It really is a side story that re-visits unanswered questions from FC/SC and prepares the players for the sequels that follow. Though the majority disagrees with me, I like The 3rd better than SC because it's so unique, for both JRPG and Kiseki standards.
Considering the steady progress on Cold Steel and its sequel, I'm not too concerned about the series' future. SC will continue to sell like FC, and it's hard to resist Cold Steel after having finished SC. Even though Cold Steel isn't the strongest game in the series, its cliffhanger and brilliant sequel will undoubtedly draw people to stores again.
As far as I can tell from XSEED's blogs, the localisation of Cold Steel and II are advancing smoothly. The 3rd requires profound knowledge of the series, the Crossbell arc included, so I think the team currently working on Cold Steel II is the best team for the job -- but they need to finish what they started working on first.