Prism
Explorer
That would be a complete and major change of thei "CR policy" to date. It would make Tiamat now look very lame indeed (not that I though capping actualy deities at CR25 didn't make her look lame to begin with, but now being eclipsed by mere demon princes is adding insult to injury for a lesser deity).
The combat ability of a deity should not be a reflection of their influence. If a demon prince is physically more dangerous than a deity then I don't see a problem with that - especially that demon prince. Also, we only saw stats for Tiamat on a prime where she does not have huge influence. Maybe she has different abilities in her own realm in hell or on a world like Krynn. A deities power should be a combination of their own prowess and an element of power derived from their worshippers. In AD&D many of the gods where less challenging in combat than demon princes and arch devils - I remember because we fought a bunch of them for their stuff