Is it true that WotC has stated that for all future material the Essentials versions of classes are the presumed version being used.
I realize that in no way means that you can't still use the older version side by side. Nothing from the original books is mechanically out-dated, as was the case in some 3E stuff. But, assuming this is true, wouldn't that still create a feeling of obsolescence to the "old school" options?
It entirely depends on what it is they are designing. If they are making entirely new classes or new builds of existing classes... I imagine they might very well decide to stay with the Essentials format. But all the Essentials format really means is that rather than having a power choice at every level... sometimes you'll have an assigned ability instead. Does that really affect anything? Only so much as stuff like the Martial classes won't have new Daily powers created for them anymore... but then again, after PH, Martial Power, and Martial Power II... it's not like any of the Martial classes need any more Daily powers.
As far as I'm aware... the Essential Arcane, Divine, and Primal classes still use at-wills, encounters, and dailies, which means those powers are all still useful for the classic 4E classes. And the feats work across the board as well. So new "Essential" stuff that is designed will basically be universal 4E stuff... with the exception of the occasional level abilities that are created when a new build is made. Speaking personally... if the Heroes of Shadow book has a whole host of powers and feats plus has leveled "class abilities"... I will forgive them for designing those things that my non-Essential classes can't use. Because when you get right down to it... those abilities are such a minor focus of the character power design.