We've definitely heard much feedback to this effect, and this is something we'd been discussing quite a bit internally as well over the past couple of weeks. In an upcoming build (hopefully the next one; if not, then the one after), the respec cost is gone, and players can freely switch between all specializations with the normal restrictions of cast-time, needing to be out of combat, and so forth.
Ultimately, the intent behind the respec cost (which isn't really a new concept, dating back to 2004 class trainers) was to help reinforce a bit of spec identity through declaring a "primary" spec to which you could always return for free, and to serve as a mild gold sink. But in practice, changing specialization is a pretty significant transformation in terms of action bars, optimal gear in some cases, artifacts, and so forth, and already not something that people were taking lightly. I suspect the cost will not be missed.
An area that has appeared to need a bit more friction, however, is actually talent changes. Especially with no reagent cost at all now, it can be all too easy to activate AoE talents before larger packs of enemies in a dungeon, and then switch back to single-target talents before a lieutenant or a boss. Or someone might switch to a passive movement-speed talent when traversing an area, and then back to something functional before entering combat. At that point, we're often hardly talking about a meaningful choice at all, but rather a nuisance of extra button-presses or UI navigation before you can use your desired talents.
And so, alongside removing the respec cost, that same upcoming build will also restrict the ability to change talents when away from a safe area (defined as an area that provides the Rested state). We currently plan to give Scribes a recipe to craft a consumable Tome that can be dropped in order to allow all nearby players to retalent freely for a time - particularly useful for group play.
A couple of clarifications, one of which will probably be a relief and the other likely less so: The Inscription consumable as currently planned would be something that anyone could drop, not a profession-requiring item like a Jeeves. But, in terms of the materials required, we're thinking of something that's more aimed at groups, and probably not the sort of thing an individual is likely to carry a stack of and use freely.
This is clearly more restrictive than the way it works in Warlords. Why would we ever add restrictions to something like this? Do we just sit around and amuse ourselves by thinking of things to take away from players? (We don't.)
Ultimately, for a choice to be meaningful there has to be some associated cost or trade-off in the process. Do you want to eat your cake, or do you want to save it for another time? If you could do both, that wouldn't be much of a choice.
When it comes to talents, which serve the primary purpose of customization and differentiation, consider two extremes in terms of how they could be handled. Please, take a moment to think through the following scenarios:
First, what if you could switch talents freely, at any time, including while in combat? You'd effectively no longer have a talent system - you'd have a spellbook with another 21 active and passive abilities in it, with keybinds to swap between them as needed. Every player of a given spec would have identical capabilities, with some cumbersome interface management required to swap among them on the fly.
Second, what if you could literally never switch talents, short of making a brand new character? Choosing a talent would be a far, far weightier choice than any decision you currently make in the game (other than choosing your starting class, I suppose). Some favored cookie-cutter specs would emerge, but with 2187 different permutations of talents, there'd be significantly more variety among players. But some niche talents would likely go almost entirely unused (though players who did choose them would be invaluable when those situations arose). And feeling like you'd made a mistake, and were stuck with one or more talents that you didn't like at all, might completely sour your enjoyment of a character.
Anyway, we are of course doing neither of those things, but there's a full spectrum of choice that lies in between. We've generally moved away from the second scenario and closer to the first over time (years and years back, respecs were so expensive in relative terms that players often waited for class changes to automatically refund their talents rather than spend the gold to move a point around). Other than the combat restrictions, the live game is not terribly far off from the first scenario.
There's still a fair bit of thought that goes into which talents to select for a raid encounter, where you're in combat for several minutes in a row and facing a variety of threats, and you may have to weigh whether you want better AoE damage for minions in the first phase, or better single-target burst later in the fight; whether you want a passive movement-speed increase for higher overall uptime, or an on-demand active movement ability in case you get targeted by a specific troublesome ability; and so forth.
But most other content, whether it's a single quest boss out in the world, or a dungeon that breaks down to a series of sub-1-minute combats, don't offer nearly that much variety. And so you take the AoE talent for the AoE pack, and the single-target talent for the lone boss, to the point that you might as well just have both of them all the time, which might be powerful, but wouldn't be a choice.
In this case, if you're returning to any safe area (your Class Order Hall, Dalaran, Stormwind, or whatever) in between activities, you could change talents freely with no cooldown, cost, or other restriction. The Inscription consumable would only come into play if you wanted to change talent out on the fly, in the field.