Yeah... that's not how I saw it, at least. As I recall, divine Ceremony is rather limited, divine Methods suck in that casting spells becomes very rare, and the guidelines suck in that good effects have prohibitive levels. And if you want to keep reasonable ability scores and reasonable Methods/Powers in the tradition, well... you end up with not-so-impressive supernatural powers. At least I did. Maybe I did something wrong, but I got Magic Resistance 40 (ok - something like 55 with faith points and what not), for example, not 100; Not that MR 100 would be such an insurmountable obstacle for the Order. And none of that "immunity to damage" uber powers.
Yeah, he can exploit the loophole in the magic resistance rules to throw (mundane) ice at you. And he can do some fairly powerful spells; up to level 75 - in ice only.
In my opinion - as a Might 50 creature Lord Marsyne should be defeatable by Hermetic magic, but only just barely. His Magic Resistance should be high enough to resist anything except archmagi bringing in the heavy guns (wizard's communion, sympathetic and arcane connections, and lots of raw vis). His magic should be able to mimic the Order's most powerful spells. His Penetration should be high enough to affect almost all magi - but low enough to be blocked by a devoted master of Parma. Higher-level (Might 75) creatures should be essentially untouchable by Hermetic magic, and much more powerful than Hermetic magi.
In all these things, Lord Myrsyne's statistics don't fit. His Magic Resistance (50) is so low a master-magus can probably take him down without even needing to pull any of the big guns. His magic can reach respectable levels, but not close to what archmagi can pull off (level 180 spells and more). His penetration is harder to evaluate, but that actually seems better - Parma 10 will block him, and so will lower Parma with some Forms, so that it seems roughly alright.
Bottom line - Lard Marsyne will fall to Hermetic magic too easily, and his magic is too weak in comparison with top-level Hermetic magic. Or in other words - magi's power needs to be brought down, and Marsyne's Magic Resistance needs to be brought up. In my opinion.
Yeah, the spirits can go hide in the Magic Realm and cry for their mamma while we toast their aspects for the evening's BBQ. ...
Magic should not trounce the mundane, in my opinion. If the mundane forces aren't a threat, the whole setting becomes a farce. All those castles, all those knights - don't really make any sense, and all those histories that fill ArM books are useless.
Leveling cities is something angry gods do, not pissed-off apprentices. And there should really be only very few things with the power to do that. An angry mob should be a concern for most covenants, and an angry bishop even more so. A castle should be respected, an army feared, a crusade should be a nightmare to be avoided at all costs. Wizards should belong in the setting, being at low-enough power level to participate instead of overwhelm it. They can join an army, perhaps advise it; they should not replace an army, or destroy it. They can live in a castle; they should not erect one magically with ease, nor should they destroy their enemy's castle with a wave of their hand instead of a long siege. They may bargain with kings; they should not laugh at their meaningless "knights" and "armies" and ignore those crown-wearing fools.
Magi's power needs to be brought down. Or else - the setting needs to be seriously altered to make more sense; perhaps a High Fantasy setting will fit the current power levels.