It pretty much is a £50 one off payment the way it is set up atm. When I saw the amount of buffs in the cash shop I thought Jamie was trying to get a job at Activision or TRION, there is a ridiculous amount and I hope he consolidates a few of them. However, in terms of actual cost it's really not as bad as you may think due to the Hunt Gold system he has implemented. I was concerned about the costs so worked them out (obviously it's still in Alpha so he may change some things but last time I logged on this was reasonably accurate:
https://docs.google.com/spreadsheets/d/1P4sFlZjvwYyrwoL100TbleLRifNszm6pRCcYtjc4L1g/edit#gid=0).
With how it is currently set up it's comparable to buying a £50-£60 founders pack for a few day head-start, similar to how a lot or MMOs seem to be nowadays. Whether that's acceptable or not for a Mir private server I don't know as I have little experience with them.
As for class mechanics I do agree, IMO Jamie's fear of class imbalance has homogenized the classes a little too much and even dumbed-down the playstyle in PvP (especially for the sin). Which is a big disappointment for me, the Mir 3 Sin was one of the most fun classes I've ever played in any MMO and that was on an the almost unplayable laggy global server. I can't deny the Zircon version may actually be better for the majority of Mir 2 players who seem to prefer the simpler class set-ups but I will miss the complexity and skill synergy it had on global.