Do you agree with the sentiment that giving players the ability to create incredibly powerful, nigh unstoppable characters (MoTB) is less important than staying true to rulesets and rulebooks? (DnD)

I don't think either is especially virtuous. Rules exist to give the player a framework for playing the game. The goal is for the game to be fun. For most people, being unstoppable gets boring pretty quickly. RPGs often allow people to eventually reach that point, especially if min-maxing, but if it's near the end of the game, that isn't necessarily a bad thing.

If a min-maxed character is capable of taking out end game opponents and challenges with ease, it's probably still a challenge for the non-min-maxer. As long as people are enjoying the game and feel rewarded for the character choices, I think it's fine.
Also, a lot of licensed rulesets are flawed or even outright terrible in their original forms. Staying slavishly devoted to an already bad ruleset when it gets translated into a completely different medium is a bad idea.    
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What are your thoughts on players "min-maxing" and using all kinds of tricks and maybe even exploits to create more or less game-breaking characters in RPG's?


That's part of the game. It's the system designers' job to make that rewarding without resulting in severe imbalances between the min-maxers and more casual players. Completely removing the ability to min-max (or the power of min-maxing, which amounts to the same thing) can lead to the player's choices feeling unimportant, which I think is bad in games in general and especially in RPGs.
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