I'm sorry but you are misinformed. The reason why ef took so much time to be released was not MangaGamer fault. Minori was the one taking care of the builds for it so that MangaGamer could test them afterwards. The problem is that Minori took a long time to send each build. For example, if you look at other titles MangaGamer releases, you won't see them taking this much time.
Oh, and before you mention something about Chou Dengeki Stryker also taking a long time to be released, the reason is because the game is still with Overdrive to finish scripting. Again, this isn't within what MangaGamer has control. But of course that the customers usually don't know this.
Regarding Da Capo III, as already said, Mangagamer is working on it. In fact, after the moment they sent the C&D notice it became obvious that they'd be releasing a localized version of it.
Have you heard about Da Capo III anime? The Da Capo III anime just covers the prologue of the VN. MangaGamer staff already said several times that the script is as big as Koihime Musou. Doddler even twitted about it some weeks ago (December 13 to be exact). Also, for translation consistency, only one translator is working on it.
If MangaGamer didn't release nukiges they'd probably be out of business by now or would be just another JAST taking a long time to release VNs. It should be obvious by now that above all, JAST is interested in making profit of each title. To complement, as far as I know they have very few staff members.
Going back to MangaGamer, the fact that they release a lof of nukiges certainly gives the impression to newcomers that they're simply a porn company and basically don't release story titles. This is why so many people support MangaGamer re-branding itself which I agree. The current market (reads: people who actually buy story VNs) isn't big enough to support the continuous release of story titles.
Of course not! Take Eroge! ~Sex and Games Make Sexy Games~ as an example. I'm pretty sure I haven't read to this day a more erotic VN than this one. Oh they were good days!
Btw, it's good the see a fellow Portuguese (yes, from Portugal) around here.