I disagree. Hearthstone's rules are extremely clear. There's not been even one time where I'd go to use an effect, and NOT know about some sort of conflict or something. Taunt + stealth? Done that frequently with a rogue deck, knew what'd happen with it before I did it. If something STARTS with taunt & stealth, that too makes sense. You then have a minion that can taunt for you when ready, but is first available to get in an attack of it's own, since the stealth will keep it on the board for one turn.... you cant directly blast or hex/morph/whatever something that's stealthed. Which is the "hex-protection" that you say isnt there, if I understood you correctly. Stealth is the best defense against the transformation cards. There are other ways to deal with them as well, but that's the simplest.
Also.... you can dispel effects and such.... there are cards that exist exactly for this purpose. That's what "silence" is for. Hell, there's one minion (Ancient Watcher) that is a very powerful one for a very low cost, BUT, it essentially starts out locked down.... it cannot attack. You *have* to cancel the effect on it to use it offensively. It's a frequently used card, too, either by putting it out and theen having another minion cancel it's text, or by having another minion give it taunt (and taunt is another thing that can be cancelled, for that matter). Things like buffs or debuffs or other status changes are cancelled by this also.
The only problem with the card texts/whatever is that occaisionally you get something like Ysera, which has you "draw a dream card" but doesnt tell you what in the hell the dream cards are. Any card that gives "special" cards has this issue.
Other than that.... I've got no issues with the game mechanics. Balance issues? Oh yes, indeed. But only because of the low card pool. And MT:G (and no, I DONT mean the Planeswalkers games, which I pretend dont exist. I mean the actual card game) has very, very often had it's own balance issues, and will continue to have them as new expansions are introduced, and old ones cycle out. They are nearly unavoidable in a TCG.
As someone who has been playing M:TG since Ice Age (omigod that set is soooooooo old now), I surely aint seen another TCG yet that can outdo it, but... Hearthstone? No, it dont equal M:TG, but I've still found it to be a very good game nonetheless.