Perhaps an "option" for subscription can be a good idea,and those not concerned about the latest feature(s)will just have to pay the premium price as usual when they want the new features,but once the new version comes out the subscription people are already paid up.I can see how this may benefit both sides,aslong as there's no hard feelings towards those content were they are in any particular version.
Really the only reason i would leave Cakewalk is if this were implemented and the program were to lock up had i not done updates,unsubscribed or be forced to connect my workstation to the net regularly.im always hesitant of updates for any softwear for stability reasons,multiple programs ive done updates for,bugs got fixed but many times theyve come with other,more intolerable bugs than the previous,which is why i always keep copys of the last most stable downloader of all my softwear so i can always go back if nessisary.and if you must connect to the net every time,for me and i think many other will agree that would be the deal breaker,for home enthusiasts who spent a good sum of money for there computers not to be on the net everyday collecting __wear's and such,and for those who make there living this way all it would take is one day cakewalk server goes down for any reason and now there not making money that day.
Basically as long as the currently installed version keeps working regardless of the three points i mentioned a subscription method might be useful for those new feature crazed people,like me at times :-P they would have there update new feature whatever assoon as its out not the following week when they get there check.
tho paying for "bug fixes" i wont agree with,a product should work as advertised,if hardwear gets a warranty for possible defects in manufacturing then so should softwear to some degree to sell there customers working equipment,atleast for whats advertised.