I think it's better put to say that Protestant beliefs seem closer to Orthodox beliefs. In some few areas that is true but even there, the differences are vast except perhaps with the Lutherans and the Anglicans. In all honesty, some of what you believe as fundamental doctrine we see as almost completely Roman Catholic. The filioque in the Creed springs to mind.
"We’re heretics for not believing in transubstantitation, you’re not."
mm, it's not a matter of believing in transubstantiation so much as it is a matter of most Protestants rejecting the dogmatic belief that at the consecration the bread and wine on the altar table become the true Body and Blood of Christ. We reject the explanation the Latins use; we also reject that of the Lutherans and the Anglicans. But we certainly completely and dogmatically believe that the bread and wine on the altar table become the true Body and Blood of Christ by the power of the Holy Spirit. If that runs afoul of the declarations of the Latin Church's local Council of Trent, then by their standards we Orthodox may well be heretics.
"Same with much of the teaching on Mary"
The only teachings on the Most Holy Theotokos we do not share with the Latins is the dogmatic declaration of the Immaculate Conception (which I guess I would expect Protestants to embrace on account of your notions of Original Sin) and that of the Assumption, which we in fact believe but do not believe it is a belief necessary for all Orthodox Christians to embrace on pain of excommunication.
That's precisely what we believe. "Transubstantiation" says nothing about how it happens (which is, of course, by the power of the Holy Spirit), it just states in philosophical terms what happens, that in spite of the appearances of bread and wine the reality (substance) is no longer bread and wine, but the Body and Blood of Christ.