I don't see how it is BS in any logical way.
Phalanx 2, even with full merits, has less potency then Phalanx. So the solution is very simple - remove Phalanx 2, and make a way to cast it, and other spells, on others with increased duration.
Now, I don't actually think Enspells and Temper should be castable on others in any circumstances. Also, spells like Aquaveil, Stoneskin, Blink wouldn't be worth cycling on a whole party, and hardly worth casting on the tank. Phalanx already has a cyclable version with Phalanx 2, so the change would only be increasing the potency and duration (based on the change I suggested).
That would just give Barspells and the Gain Spells as the new things to cycle. As pointed out, if casting the near instant cast Barspells on everyone is too hard a hassle, you could just sub White Mage, or get a White Mage.
Since any good White Mage would just sub Scholar and get the same boosts to Gain/Boost spells as a Red Mage, you could just rely on a White Mage for this if you really don't want to cycle, but it makes it so you don't have to. Additionally, your duration would be greatly increased (Gain spells last 5 minutes currently, with the maximum between gear and full merits, you'd get 15 minutes), and unlike a White Mage, you'd have a much easier time of customizing which Gain spell each party member gets.
Or if you want to mix and match, the Red Mage version doesn't get overwritten, so if for example, one person needs Gain-DEX, and the rest need Boost-STR, you just made the party work that much better. This also applies to barspells, like if a mob has a single target air based move, and an AOE water based move, you could have the tank get Baraero, and the rest get Barwatera.
So basically, you'd just have a merit that increases duration on all your spells, makes Phalanx better, increases the ability of Red Mage's, at the cost of only really adding one more spell line you will possibly be asked to cycle. There is no BS here.
It is what everyone has been saying more or less. It would greatly improve the merit categories too, since you wouldn't have to merit one point in things just to get a spell. I hope that when SE changes this, they make all the spells appear at a vendor, but give all Red Mages with merits the spells automatically.