The unrealism mainly comes from people who don't think before nading, in the real world grenades are something you are trained to use in certain situations, and you are trained to have respect for them, because if you mess it up you can easilly kill yourself and freindlies with your grenade.
This does not translate well into RO, as many people use them without thinking, putting team mates in danger, and wasting them on stupid kills they could just as easilly have gotten with their rifle.
Grenades should be treated as an asset, a tactical weapon for use against multiple targets, to soften up an area before an assault, or to clear an area that would be too dangerous to take by other means, and above all, you need to considder where your freinds are before you even think about pulling the pin or cord.
But since people know they will respawn with two more very shortly, they don't really put much thought into them, and we see some pretty daft use of 'nades, lots of people just toss them randomly with no regard for who might be within the blast radius, and not to give them or their team an opening or a tactical advantage, but just to get a cheap kill, a kill that often makes no difference at all.
To goal of RO is not to collect kills, it is to capture and hold ground, and people should considder grenades an asset that, if used wisely, can help them advance, or repell an attack, not as a free 1 point to their own personal score.
We dont nessesarily need to see fewer 'nades, we just need to see smarter use of them, but perhabs limiting the 'nades is exactly what it takes to make players use them with some thought and purpose.