This isn't apt, because that actually alters how you play. You're hitting your Frostbolt key more often with a MH/OH combo than with staves in your hypothetical scenario, in addition to producing more damage events which turns into more procs.
It's not a perfect analogy because the different between a two-handed-Frostbolt and a one-handed-Frostbolt in terms of "attack speed" has to be expressed in discrete keypresses, unlike the difference between two-handed and one-handed Autoattacks.
However, the latter part of your paragraph regarding more damage events turning into more procs, is very relevant, I think - SMF can manage higher Enrage uptime because the hits are oftener (or have they changed that lately?)
In any case (and in the event that weapon speed/ability use differences have been completely quashed in TG-vs-SMF), the point was that in TBC, you only ever had one two-hander per PvE tier and one weapon specialization was always dominant in PvP even if multiple weapon types were available, which meant that Weapon Specialization was a non-choice: You simply took the best weapon that dropped in a raid, or took the best effect for PvP (stuns, or perhaps sword-spec)
In contrast, using a pair of two-handers versus using a pair of one-handers is a conscious choice you have to make: The game goes out of its way to make the two equal (or at least that's the intent), and acquiring a PAIR of weapons is a significant enough investment of your time and effort that you're not going to have one or the other as easily as you would have in TBC.