I have to agree with you on most of your points Maiden Ty One. I'm still struggling to understand why it is that a lot of bugs seem to be ignored or left to be addressed in later patches. For example, the misplaced "The Fall" mosaic piece bug that's been around since day 1 was only fixed with Patch 6, despite the fact that modders were able to very quickly and easily fix the problem shortly after release. I really wish someone from Bioware could explain this, and how they prioritize their fixes. To be fair, the glitch with opening doors from the wrong side, while exceedingly annoying, is fairly minor and avoidable if you remember to watch out for it. But failing to address game-breaking or progress/completion-halting bugs with due expediency is baffling, especially in cases where modders were able to produce their own fixes fairly quickly.
Honestly though, I'm mostly ambivalent about their decisions to remove exploits, even though I do agree that it's usually pointless in a single player game. Thing is, sometimes (very rarely) exploits in single player should be fixed, though only in situations where they make everything else in the game pointless; the best justification I can think of is that players who get bored of the game because they found an exploit that completely removed all of the challenge and effort are more likely to just stop playing it, especially if they aren't as drawn in by the non-gameplay elements like story, lore, etc. If there is an easy exploit that completely or dramatically eliminated how much effort or progress needs to be made to finish or complete the game, then it's possible that some players who use the exploit will get bored sooner and stop playing and supporting the game's DLC. That being said, none of the exploits they fixed seemed to be game breaking at all, and even exploits like loot and influence manipulation are minor when you consider everything else that is there to keep you invested.
For example, I admit to using the influence exploit while it was still there because I wanted to make sure that I could unlock every possible inquisition perk I could get without having to spend extra time farming influence by repeatedly filling requisitions. Sure, some people would and have filled out the Influence meter to maximum, and thus maybe removed some of the incentive to keep playing the game longer, but that doesn't stop players from doing war table missions and the non-requisition side quests since they also often provide extra rewards and also have the potential to affect the outcome of the story. If anything, all Bioware needed to do was learn from this and tweak their influence system so people don't have to grind to max it out, and thus don't feel compelled to use an exploit in the first place. So really, this exploit hardly mattered at all regarding gameplay. In fact, I argue that gameplay is the last thing that pulls new players and fans alike to the franchise; I say that what makes me and many others a fan of the series is the excellent storywriting, the depth and humanity of the characters, and Thedas, the fantasy world with such well developed lore, mythos, and history that it can rival Middle-Earth and Westeros in terms of depth and detail. Ultimately, while I remain ambivalent about fixing exploits, I will concede that it is truly unnecessary here, and that Bioware and EA did mess up by not focusing on bugs in their patches.
As for the case of the loot exploit and the amulets of power, I think that this is a case of an exploit that people wouldn't use particularly often anyway since it just makes gameplay very boring if used too much. Even then, few people would have the patience to use the exploit enough times to overpower their characters and party members, and I doubt people would want to waste so much time repeatedly going through loading screens over and over again as they fast traveled back and forth, much less endure walking to the same loot box again and again. It shouldn't have been a priority over actual bugs, but I suppose their logic was that an exploit like this, regardless of how unlikely it is to be abused, would lead to more players getting bored sooner, and thus less DLC sales. But even then, the fact that they created a bug by trying to fix a harmless exploit isn't the biggest problem for me; the problem I have is that they made such an enormous and obvious blunder, and then failed to correct or undo it in the following patch. I just find it baffling that they didn't bother to simply restore the old code that they changed, then add it to Patch 6. I can't imagine that it would have required any effort at all.
And I too have been wishing for a New Game +, and have wished for it in every Bioware game since Mass Effect 2. I never understood why they stopped doing that after Mass Effect 1. In a game like this, New Game + would make it a lot easier to experiment with different story decisions with the same character, and thus make it possible to have multiple options for canon stories in future games. I can appreciate the idea that maybe they're trying to add a feeling of finality and weight to your decisions by removing any short cuts to progress, but then the only thing that has to be carried over would be experience level, loot, gold, collections, and resources/materials. They wouldn't even have to carry over influence if they made the system less grindy. But I digress.
Anyway, the point I'm making is that Bioware needs to straighten its priorities in its patches and fixes. Exploits should not take precedence over bugs, especially the ones that mess up gameplay. I also think that they need to make a point of publicly announcing and acknowledging the discovery and existence of bugs, and at least release some statements about their progress in fixing them. Because really, I would not have been raging nearly as much as I have the past few months if Bioware had been more transparent and communicative. I remember that they used to at least post statements in forums in the past when bugs were found in previous games, like the missing dialogue for Ken and Gabby in Mass Effect 3, or the backstory glitches of the PS3 version of Mass Effect 2. If the developers and programmers interacted with their customers as much as they used to, instead of just directing us to EA's technical support, I'm certain that they would release better patches and actually address these bugs in a timely manner.