That's a little harsh, don't you think. If the classic wizard carrying a quarterstaff casts a spell, that's exactly what he has to do. Do you allow wizards to cast spells and still wield quarterstaffs?
How about other types of characters. Lots of them do more than one free action per round. For instance, a fighter with Quickdraw might move forward and ready his shield as a free action then quickdraw his sword. Are you going to say he can't do it? How about if he drops his ranseur first. Now he's up to three free actions. But apparently, if two is too much then dropping one weapon and quickdrawing another is out of bounds. (Make sure to tell all your players not to bother with Quickdraw--it's worthless under such an interpretation).
Or archers. Drawing ammunition is a free action. However, with your limit of one free action per round, there's not much point in rapid shot, haste, or extra attacks from high BAB.
For that matter, thrown weapon specialists are right out despite the text of Quickdraw that explicitly allows someone using thrown weapons to make a full attack. (That could be as many as nine free actions (haste, rapid shot, greater two weapon fighting, and a +16 BAB))
And, of course, the limit on quickened spells is entirely unnecessary with a limit of one free action per round. Why, in your game a wizard can't even cast a quickened true strike,




his crossbow (a move action), load it (oops--there's that pesky second free action), and fire it in the same round.
And God help any PC who actually wants to shout a battle cry (free action), quickdraw a weapon (oops, a second free action) and charge his enemies. That too is apparently unreasonable in your game.
In short, the DMG allows limiting free actions to a "reasonable number" but one is not, by any stretch of the imagination, a reasonable number. (I don't see what you're so worried about with a caster using a two handed sword and still casting spells anyway--it's not as if it's a horribly overpowered combination anyway.)
Infiniti2000 said:
This is allowable per the RAW. It's also not allowable per the RAW. For instance, I personally would disallow it, citing the "there may be limits to the number of free actions you can perform in a turn" rule. You can take your hand off your greatsword, but then you no longer threaten for the remainder of the round (until the beginning of your next turn when you can place your hand on the greatsword again as a free action).