How bout a weapon as fast and strong as a whip, but incapable of training defense. It also hits crush instead of slash.
apparently, they changed it form the transition to rs2 from rsc so that weapons would have speed, in the hope that more people would use the other weapons that were being ignored (everything except baxe and 2h). I never played rsc, I read it in an archive when I asked this question to someone who gave me a link. I don't have the link myself, but im pretty sure it was detailed in a 2004 update.
Instead, everyone uses the perfect balance of speed and power, schimmy, and ignores everything else.
The schimmy either needs to be nerfed somehow, or the other wepons need to get faster (in the case of weak ones) or stronger(in the case of slow ones) so that they can all generate decent melee exp. Also, the whip is too much of a juggernaut. It needs a decent competitor that can be acessed by an average player.
I believe scimitar will not be nerfed, and the specs of the current weapons will not be changed, unless there is a new RS release, like RS3. That is to say that Jagex will only add in weapons with different stats, to try and balance their game more. I think a weapon as fast as a whip, and as strong as a whip, but can train strength is needed. There needs to be some downside to this weapon though, it has to degrade, need sharpened, etc. Then the base will split between this weapon and the scimitar.