Are you trying to be difficult? You couldn't grapple him if you were using a sword and shield in the first place.
To answer your question: Yes. But not simply for the sake of difficulty. It should be difficult to sell a bad idea, I'm just doing my job.
I can't grapple with a sword and shield? Agreed. But then, I can't grapple someone bare handed under this system. So if I'm going to have a guaranteed failure on a special maneuver, I'll at least choose the failure that does some actual damage.
Grab dat spiked gauntlet and/or a level in monk.
Yeah, turn my insignificant non-lethal damage into insignificant normal damage. That will fix everything.
The target will still choose not to be grappled, since I'll do the exact same damage either way, whether it's the D3+STR, the D8 + Str of the Monk or the Claw/Claw/Bite/Rake of a Tiger with Improved Grab. The choice is: Take the damage once, now, or take it every round with no hit roll required.
A cheeseburger is smart enough to get that decision right. So... I just need to fight opponents that are dumber than a cheeseburger. That's the ticket...
Sorry if my sarcasm offends. Playing it straight: I laid out the failures for the various D&D combat maneuvers, and you weren't persuaded. Looking at the broader picture, the proposed rules lets the opponent decide whether or not to be put at a tactical disadvantage when someone tries a special maneuver. Clearly, no one will ever accept that option unless the alternative is immediate defeat. And if I can deliver immediate defeat to an opponent, why would I waste time and effort on a special maneuver?
What it boils down to is that the only time when a special combat maneuver will work is when it's a mistake to even attempt one.
Logically then, I should never attempt one.
Slipping back into sarcasm (with apologies), the rule achieves its goal of simplifying the combat maneuvers, in that nothing could be simpler than a rule that never gets used.