These are the scenarios that I am imagining (considering that Heal will really need SPR and/or INT investiments)
PvP - the Full CON Maxed Ein Sof Kabbalist matched against you will be easier to deal than now. And due to the full CON investiment, it will not deal amazing damage against you neither heal as a Full Support / Heal invested character would. Also, if you are this Max Ein Sof Kabbalist but decided to go for the damage or support path, you can still have a good usage of your Ein Sof skill with a better HP increase to be able to survive more. The major impact here is that today you are able to do both, being able to survive with this absurd Ein Soft multiplier and perform good heal/damage on top of it
PvE - we have the regular scenario (CM5, Dungeons, grind parties, lower floors of ET) and the meta/hardcore scenario (330 Raid, Velcoffer, Higher levels of ET, CM7): If you character is a Full Support, you will make everybodies’ life easier with a better heal oriented class than a Full CON one, judging that Full CON would not give the maximum heal capacities after changes. In regular scenario you could give Ein Sof to anyone who would benefits better, since there are no huge threads inside these contents (and if INT would be the major stats, your magic damage Cleric could also perform as a healer, and this is why SPR as major healing stat would split even more the roles of support and dps). At the meta content you would need to be FS to properly heal your party, then you can use the improvement made for low-CON of Ein Sof on yourself, or if you are handling the damage well, you can give to your Tanker, who probably have better CON investiment, so he can perform his duties even better blocking, aggroing and receiving hits. BONUS: if you build a good party for meta content, you can still have CON, INT and SPR (linker, thauma, etc), and then these changes proove again that would be good for party play and spliting roles.
It is more intricated than just how Ein Sof will work alone, but how everything could fit together. Again, these thoughts are all speculations and heavily depends on how these heal changes will impact the game. But I see logic in a Full CON not performing the Full Support role as well as a FS character. These healing changes can cause bigger impact than Ein Sof.
