I agree with the spirit of your post, but why do we have to go the nonsensical route if we can have great ideas that make sense?
Cybernetics, power armor, laser, tech, etc.
Well, largely going back to the individual taste argument, I just don't consider the sword to be as nonsensical as some others do, at least in relation to the rest of the setting.
I can buy a sword made out of the right materials using the right manufacturing techniques with all this advanced tech, can be made and be capable of cutting through the armor available in the setting. That may well be bullsh*t, but it's the kind of bull I can accept as part of my willing suspension of disbelief. I find it far more believable than a light saber- just on general principle of 'how can you have a laser that only reaches a yard long' logic.
For the record, I know the official explanation and I'm willing to accept it as part of Star Wars' internal logic, but I wouldn't be willing to accept it as part of ME's. That would be where the line is for me.
Hell, I'm more inclined to buy the over-manufactured and over-designed sword than I am to buy the omni-tool and omni-blade. I do buy those as part of the setting, but they're kind of technobabble handwaves in and of themselves; here's a tool you hold on your hand and you wave it over stuff and nano-machines do whatever you need it to do, including making a knife, that may or may not be on fire.
And I liked the omni-blade. As for why I'd like to see a couple classes who use a sword as their back-up weapon instead of the omni-blade, well, I feel there is a reason why throughout most of human history most bladed weapons have been gripped in the hand as opposed to affixed to the wrist. I think that adds a level of versatility as opposed to the omni-blade which is more "I'm going to punch you, just with this sharp thing."
Went off on a bit of a tangent there.
Anyway, I suppose another aspect of it for me is, for better or worse, I see these ideas as being already established in the game, and I would like to see them done well and be utilized instead of being forgotten. Even ignoring phantoms, I never had the separation some people did of the MP classes and the main game. The thought of "this is just something for multiplayer, it doesn't really exist in the lore" never entered my mind. I just saw the classes and thought "Ah, ok, this is a thing in the setting beyond the usual scope of what we've seen. That's cool."
So I always assumed that the MP classes were canon. Never broke my immersion. I just found it interesting to see what concepts they came up with. I liked some more than others - was never a huge fan of how the Slayer played, for instance. And I did recognize that there was some gameplay segregation going on - phantoms one-hit killing krogan despite their redundant organs and everything. But there's gameplay segregation in the games, too - I never bought that Ashley would be capable of taking out Wrex with a single shotgun blast, for instance. Is the shot gun blast a somewhat more realistic one-hit-kill than the sword? Yeah, not disputing that, but it's still a guy who can tank rockets to the face, so that's just a matter of degrees, really.
Anyway, in regards to some of your suggestions; power armor and cybernetics are obviously toys I'd like to see them play around with in terms of further diversifying character builds. I'd point out that the Shadow and Slayer do explicitly use cybernetic implants to improve performance on the battlefield. I'd also think those elements are well suited towards justifying viable melee characters; there's only so much power armor and cybernetics are going to do to help you shoot. Reduce recoil, carry a bigger gun, improve aim if you have cybernetic eyes, that all helps. But at the same time that can go towards increasing speed, power, and defense in close combat situations as well.
I'm not looking to become a GeeDubs style Space Marine. I'm not looking to become a Metal Gear style break dancing cyberninja. I'm just looking for more options to build a character, more variety in what characters can do, more play styles becoming available and viable. Bioware's put some of those options in the series already; I don't see a reason not to run with it.