Hi Amanda,
I have used a liquid eyeliner for a few years now and find it works pretty well with me, but you do need practice that is for sure.
I wouldn't feel too discouraged by your recent experience though. When my usual eyeliner ran dry, I too was attracted by Rimmel's 'Exaggerate' product. As you say it does have a fine pointed tip, but it is quite a short stubby brush. I couldn't get on with it at all and the 'Rocky Horror' finish you describe is very accurate!
I quickly returned to the tried and tested. Try Rimmel's Professional Eye Liner. That comes with a much finer brush with longer bristles and is so much easier to apply, particularly if you are looking for a fine line. It is still an acquired skill, but very much easier than the 'Exaggerate' product.
One other thing I found that suited me at least, was to use brown instead of black. A subtle difference, but I like it.
Hope this helps?
Emma.