At heart, most Players are min-maxers. A player generally wants his or her character to excel at something. If a non-Hermetic magical tradition excels at some area beyond what Hermetic magic can do and the non-Hermetic tradition is better than the Order of Hermes in that area, then the non-Hermetic NPCs will be better than the player's character in his or her chosen area of specialization. If this happens to your character, I would imagine that you would not be very happy.
One way to get around this problem, of creating traditions that would make existing characters less desirable to play and offending players, is to make hedge traditions weaker than the Order in most areas, but comparable to the Order in one specific area. It is also possible to make a non-Hermetic tradition interesting and desirable to play by making its magic very different from that of the Order.
I tried to do this with the Learned Magicians. They are not going to overpower any Hermetic magus, even in their area of expertise, but they can do things that no Hermetic magus can do. They have spells that influence luck, fortune, or chance. Although Hermetic magic has the ability to mimic some of the mechanical aspects of the Learned Magicians' magic, strictly speaking they cannot affect luck. So in this area, the Learned Magicians excel beyond the Order of Hermes. They can also create short-term magical items in a matter of hours, while it takes a Hermetic magus at least one season to create any magical item.
Likewise with the Gruagachan, they can mimic Hermetic magic in several areas: they cast curses and blessings, which Hermetic magic can mimic mechanically; they cast shape changing spells, which they can do more easily at low levels, but cannot surpass Hermetic magic because of their lower casting totals; and they can create simple illusions, where they cannot match Hermetic magic in complexity. They will never outgun a Hermetic magus, especially a specialist, in any of these areas, but they can do a couple of things Hermetic magic cannot do. They can grant a character Visions, sure it's not an earth-shattering power, but it's something. They can also use very non-Hermetic Ranges and Durations. Finally, the can remove their souls from their bodies to make themselves virtually immune to physical attacks. So, they can't outgun the Order in things it can do, but they can do things that the Order cannot.
Finally, if your characters are outgunned by MM 30 creatures, they are straight out of Gauntlet, creating strict generalists, or haven't read and utilized the Arcane Connection and Penetration rules properly.
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