Personally, I don't want lock-bashing or open lock spells in Skyrim because they would render the whole lockpicking skill tree useless (well, it's already useless as I regularly open master locks without any training while breaking less than 5 lockpicks, but hopefully that's something mods will eventually fix) but I enthusiastically agree with you that most of the quests in this game need alternative solutions for different playstyles. Your ideas for persuading a guard to help you with your investigation or tavern brawling your mark's lover to get a house key are excellent and I really wish more quests had a variety of creative ways like those to complete them. Speech in particular is a sadly underutilized skill in quests.
If anything, its a perfect example of why the lockpicking perk tree needs improvement. They should improve it instead of holding back other features/abilities to make this one viable.
But lock-picking would still have its uses though. Bashing would be brute force, risk breaking your loot, put you in danger when bashing through a door with enemies waiting behind, make tons of noise, and you wouldn't even be able to bash through everything.
Stop whining, its not hard to do if you understand it. Don't suggest bashing locks or a unlock spell, as the lockpick skill isn't thief exclusive and it isn't difficult. Lockpicks are so easy to find/buy, considering you can pick master locks at any level using lockpicks. This isn't a problem.
Oh the minigame is incredibly easy. They might as well give us a freebie. It takes no effort to have 99 lockpicks in your inventory, and open even Master locks within 2-3 attempts.
Its not a matter of difficulty. Its a matter of roleplaying, a matter of choice, a matter of STYLE. Have you ever read any books? Have you ever watched any movies? When do you see huge warriors have the delicate touch needed to open a lock. I should absolutely suggest bashing locks and unlocking spells because this is a game about choice, a game about designing your character, and designing his style. Forcing something this specific down my throat is substandard for an Elder Scrolls game.
As it stands, I can and do pick locks even on my warriors and spellcasters, and just use my brain to say, story-wise that he's kicking the door down, or using his magic abilities. But a bashing feature and magic spells are not difficult to code. I have sufficient experience in game design to know what this entails. Its also been modded into every single Elder Scrolls AND Bethesda-based Fallout games.
Even if they weren't going to add new ways to open locks, they should AT LEAST offer alternatives to getting objectives completed during broad-audience quest lines such as the one's I mentioned in my original post. ESPECIALLY warrior-based quests.