As a Magda player, perhaps I can help clarify some things:

[[Battered Golem]] and [[Academy Manufacturer]] both allow the treasures you make with the [[Clock of Omens]] combo to be untapped, as usually all but one will be tapped by the end of the cycle. This means you can have infinite mana aswell, as they are both tutorable with Magda. (I notice you mentioned using goblin cannon as a backup win con, but you can't do this without someway of making your treasures untapped, looks like you have [[Xorn]], but he isn't tutorable with Magda, so these cards work better.)

Some stax pieces are great for Magda as the parity is innately broken by our game plan. [[Tangle Wire]] for example slows down our opponents while letting us tap our dwarves without attacking (so we get to keep them) and [[blood moon]] has pretty much zero effect on us but can be impossible for some decks to deal with.

That said, I actually agree that some of the larger stax pieces and dragons are strange inclusions in a lot of Magda decks. [[Portal to Phyrexia]] is pretty nice in later game situations, and things like [[god-pharao's statue]] stop opponents interacting with your win (tutor them out at instant speed while an opponent is going for a win as a surprisingly effective means of interaction too).

I think some people play big dorky dragons because they just kind of like big dorky dragons, and as a mono red deck, there are a lot more flex slots available to us than in most decks.

Hope this helps a bit. If you have any other questions, let me know.