Those Rontos only look ok as extra background detail when they are out of focus or obscured by motion blur (the CGI wasn't even up to the state of the art of the day and has dated terribly).

I suppose they do add to the feeling that it's an alien world with alien creatures (just as the Banthas and Dewbacks do) but only when they look convincing.

Often the Tauntauns don't look convincing in ESB (which I know Ady is going to tinker with, or already has) and people accept that because of the limitations of the day, not because they aren't really there half the time.

I don't think the crime is having them there it's having them there looking out of place and I think Ady struck the right balance with them and the CGI Dewbacks.

At least we don't have the silly painted on Jawas swinging around them and construction droids beating the crap out of Imperial probe things now.