A lot of people have been making threads lately about perk reallocation, how we need to be able to "respec" (what is this, World of Warcraft?), and how we need to be able to re-spend perks that we already learned.
This makes zero sense and will never happen, for numerous reasons.
1: Relearning perks is not logical. Taking a perk means you take on that knowledge, meaning you "learned" it. You can't just "forget" things.
Say I want to go to college to be an electrical engineer. Say I've been an electrical engineer for 10 years. Well, all of the sudden, I want to be a zookeeper. I cannot just "forget" how to be an electrical engineer and then suddenly be a zookeeper. Life doesn't work that way. You don't just forget things. That doesn't make any sense at all.
2: Crafting. Say you completely deck out the Smithing tree, get ALL the perks, Smithing at 100, you craft dozens of pieces of high quality gear, you improve these pieces via the tables and grinders, and then BOOM! You forget how to do that? So what, you crafted legendary items and then you lost the ability to do so, netting you essentially items you don't know how to make? That makes zero sense. It doesn't work like that. It would also be absurdly overpowered, considering you could just "get" the best things and then "lol sorry I wanna be a CHEMIST DUDE" and then "respec" to being a master potion maker? No.
3: Choices need to matter, live with the consequences. When you make choices in this game, they *should* matter. Making this game an MMO where you just flow with the wind and do whatever you want without consequence is not a fun way to make TES games. People want choices, people want things to matter. That's why there are so many threads on the boards about how completing quest lines don't matter at all, and it impacts the game in no way. That's not right, and people don't like that.
4: Replay value. Reallocating perks would *kill* replay value. If I wanted to just switch "specs" and be a mage, I could do that. That's absurd. This is not World of Warcraft. If you want to be a Mage, be a Mage. If you want to be a Warrior, then make a Warrior.
So yeah, perk changes will never happen.
I would like to just respond to your observations. I realize I'm in the minority here, so no need to attack me. This is just my opinion.
1. Honestly, I feel like this isn't a good reason to not do something. For all intents and purposes, this is a video game. If you were worried about if it is possible to do in real life, how are you ok with dragons, magic and raising dead? I know I don't play games for realism. If I wanted realism, I would shut down my PS3 and go outside. If you are going to reject someone's idea based on something you are concerned about, I would appreciate that concern being true and for the entire game, not just one aspect.
2. I use the same counter-arguement for this one that I used above, but: I could put absolutely no perks into smithing or enchanting and still wear these items. I don't need the ebony perk to wear ebony armor. Although one thing I would agree with is that if you want the ability to make the best, it would be overpowered to be able to make the best, drop the perks and then put it into something else. Which is something you didn't point out.
3. Are there really any consequences in this game that can make or break your experience? Other than the civil war quests, there really isn't anything that comes to mind. And even the civil war quests just involve a few NPCs being moved somewhere else. I mean, hell, you kill an incredibly important person in the Dark Brotherhood quest and yet absolutely nothing happens to you. I mean, if you want to argue consequences, argue for the game in its entirety.
4. Ah, replay value. I would like to point out a certain game: Borderlands. This game, for those who don't know, is a FPS/RPG hybrid. You get a decent skill tree and an action skill. The game allows you to RESPEC for a nominal fee. I've played this game 10x more (3 different characters, 100 hours each) than Skyrim and yet, I have respeced my charecters numerous times. If a game is good, and you enjoy the game, more than not you will keep playing. Another thing to note, is this option would be just that: AN OPTION. No one forces you to do it. If you had a huge problem with a side quest's plot, sure you would complain, but would you do it? Of course not. Not if you didn't want to do it. Does anyone complain that there is a choice to choose sides for the civil war? I don't think so.
Long story short, I feel as though these reasons are reasonable, there are other things that should be noted. Adding a RESPEC option will not detract from your personal gameplay, only add to others'. Nor will it detract from replayability. The quests don't repeat themselves, nor is there a second playthrough. I shouldn't have to go through another 30 hours of gameplay to switch a top-teir perk with another. Plus, why lose all the loot I had? Most spawns are random.
This is really just my opinion.