Ph aint so bad as you think, just add dolomite lime to original potting mix and no probs and perfect pH, runoff will get lower pH the more ferts you add. Dont read into it too much.
Miracle grow is great stuff, problem comes cause people aren't use to it. Can be hard to judge the fert levels of the time release ferts and most isnt suitable for seedlings, need miracle grow seedling soil for that. All this being said with a couple of grows to practice in it you will find it just as easy as any soil and less worry about the ferts.
Most growers seem to like miracle grow if used for the veg phase as they have to add very little ferts till flowering when they repot up to a flowering soil. Its not the bad soil you think it is and for weed can be a bit tricky to get the hang of it but some tulips or pot plants round your mothers and its the perfect soil for good growth and without the need to fertilize.
Miracle grow is slowly branching out into doing normal soils without the time release ferts which will match any normal soil on here more or less, i can get some recently and not seen it before but has turned up at my garden centre. Miracle grow is fine, like anything it just takes practice, there will always be lovers and haters of it. The lovers tend to be the better growers or have gained some better experience. Peace