I have absolutely no problem putting advice in the "core" game for a play style with which roles are important. I have absolutely no problem with some options that let you "turn on" roles with in the game rules. I do have a problem with roles being "on" in any mechanical sense (including tags or keywords) in the "core" rules, because it would keep people from playing.
Do you really consider a power keyword to be part of the "core" rules that you are forced to deal with? I mean... it's a keyword. It's as easily disregarded amd ignorable as the fluff descriptions of the 4E powers we all see and pretty much read right past nowadays. If the Fireball entry in the next iteration had a keyword list that said "Arcane, Evocation, Fire, Implement, Striker" (for example), why does that cause such concern? And why does the "striker" keyword need to be left off the list so as to not alienate players who don't like Roles... but we leave on "Evocation" even though it might alienate those BECMI players who didn't use or like Wizard Schools? Do we just eliminate all keywords altogether so that we don't alienate
ANYBODY? Are we really going to force the designers to produce a spell list for the arcane classes and NOT include a "role" keyword... and instead make them reprint the entire list in an entirely separate book that includes the ideas of roles just so the role keyword could be added at that point? Doesn't that seem sort of a waste of time and space?
Here's a similar situation which helps clarify what I mean.
Players of 1E and 2E for the most part did not use grids. Their spells had ranges in feet/yards etc., and distance between players and monsters were pretty much guesstimated during play. Are we now expecting the designers to NOT possibly include in the rules for Fireball (as an example)
Range: 100 feet in a 15 foot burst (Area burst 3 within 20)
...because heaven forbid we offend the 1E and 2E players by including the numbers in squares right next to the range in feet? Are you saying we are now "forcing" these old school players into rules they don't want by including ALL the alternative rules in same place? That squares are now "core" because they are included in the spell description?
Can't we go into this with the expectation that the rules will probably include
all the ways for them to be interpreted via your edition of choice, and yes... you as a player and reader will just need to
gloss over those small, niggling keywords, definitions and numbers that you yourself won't use, just so that the whole book doesn't have to get printed a second time to now include them? Is that really too much to ask?
And if you say 'yes'... then I don't think you're ever going to be happy with the game that gets eventually gets produced, because I guarantee it will include info attributable to all the editions, much of which won't actually be used by you depending on which dials and knobs you chose to play with.