If it is CRP based then the core of the team will be exactly the same. If anything the only changes would be additions.If that it not the case then those complaining probably wouldn't want to transfer anyway.Well to be fair Cyanide claims they will be rebuilding the game from the ground up which will mean that all DBs involved will be rewritten. If they were just going to do a simple port over with newer graphics than they could just grandfather the teams over.
Grandfathering teams on total reconstruction of their game design is going to be expensive and extremely time consuming to the point that it really would not be the best business decision they can make. It may be extremely difficult to almost impossible depending on how high of volume of teams that are on the leagues to make a great port over.
It's a shame, but at the level of difficulty that Cyanide will face. Chances are really good that you will need to start over.
The main complication IMO is the matching old accounts to new ones. I guess they figure that it is not worth the hassle. This kind of functionality is the first to be cut when the schedule starts to slip. It is sure to slip so you probably wouldn't have got it even if they were promising now.