It's not harsh. Those games were terrible. The characters acted stupidly, the story was bad (in the case of BN, also full of plot holes), rewards were based on grinding, translation errors were everywhere, and even the music was largely mediocre. BN did try to have a somewhat interesting battle system (which SF screwed up), but it's nowhere near good enough to make up for every other aspect of the game failing. They were cheap RPGs with a development cycle of a few months each.
Well, you might think they're terrible games, but I don't. I don't see much that went wrong with with the BN or SF series. I don't remember the characters acting overly stupid in either era, but I haven't really delved that deep into their personalities as I've only played a few BN and SF games(1, 2 and 5 Team Protoman, and 1 and 2 respectively). As for the story, out of the games I've played I found the story to be somewhat interesting but nothing really exceptional. But I'll be honest, if I wanted to play a game with deeper stories, I'd play something other than Mega Man. I don't look to Mega Man games for deep stories.
Grinding for good equipment is something that exists in RPG-style games as a whole. It's just something that comes with the territory so that's to be expected. But in Mega Man's case, getting good chips/cards relies heavily on your performance. Time may be a factor in this, but it's your overall skill that will determine your rewards and personally, I prefer it that way. It's just a matter of being lucky enough to find your intended target quickly.
Translation errors? Pfft. Capcom has a history of stuff like this, and it's not just them. These things are bound to happen every once in a while, so there's really no reason to get bent out of shape whenever that happens. As long as my in-game performance is not affected in the slightest, I can easily forgive those mistakes. Though it can make it hard to determine which chips do what if they have a crappy description, but hey, that's why we have the internet, right?
As far as music goes, I don't believe they did too bad but I don't really expect much from a handheld device, you know. I mean, I've always liked Mega Man music, but it's hard to compete against the big boys when you're just a handheld game in that particular era.
The battle system is the defining aspect of the BN and SF series. It's what I enjoyed most about them and BN was one of the games that got me more interested in the RPG genre(along with Pokemon, of course). Frankly, if it can do that in spite of its hiccups then I think they did pretty well. With that said, the only thing I didn't like about the first BN was the difficulty. It was too easy, even for my lower skill level at that point in time. Future entries had stepped up the difficulty, something I felt was needed.
And regarding the SF series, I like it. As far as I'm concerned, there is nothing wrong with it. I actually liked the first SF more than the first BN. It feels like a more fleshed out version of BN, particularly in the battle department. The battle system may have had its own rules concerning cards now that codes weren't a thing anymore(and consequently Program Advances), but that's ok. You could link your own streams of powerful cards to quickly down tough targets that would give you a hard time(or you just really wanted that particular SP card), assuming you had the timing to "COUNTER HIT" your target(because you needed those to gain those card strings to begin with). Oh, and you could save those card strings to create your own boss killer cards, so there's that. The "Favorites" function in the card folder made this easier. Now about the smaller arena, there's very little room for error, but any savvy BN player can easily handle it. Personally, it adds a difficulty factor that really should've existed early in the BN era. One more thing: I absolutely LOVE the transformations that existed in SF, particularly the Fire-based ones. I mean, explosive cannons? Powerful flamethrowers? Super Armor? The ability to charge your cards? Hell. YES.
But hey, those are just my thoughts on the matter. To each their own.
Regarding the final smash, I don't see why being blue should count more than being in the correct continuity/having the correct genre.
I think it's more than just their color and particular universe. They might've been chosen because they carry the spirit of the Blue Bomber in some way or another. I mean, they must be carrying the name "Mega Man" for a reason, right?
But what do I know? I'm just a guy who plays these games.