Agreed!
Don't get me wrong, I understand that all the bottles gives more flexibility and you can custom tune this and that, blah blah blah. That is true, and it comes at a heavy price.
Unless you're super versed in exact nutrient numbers for every single phase of a grow, and know exactly what ratios of this and that are needed (and manufacturers feed charts aren't going to cut it) then what gain you can get with doing it really isn't worth the cost/effort of it all.
MC isn't 100% stand alone, but it's the closest thing out there that is. Sometimes a little calmag is needed, sometimes not. Some like to use a little more silica, etc. However, as many have shown in this very thread, it's quite possible to get all the way through, and with excellent results, with nothing but MC on its own.
That's why I've got on board, and that's why so many others are too.
On top of the results and simplicity of it all, there's the added bonus of it being very cost effective to use, too!