Nope, I think you're looking good with that size rod. If the one you have acts anything like the 4/5 wt I had you have a little of both weights in that one. Take er out fishing...
FWIW, my most used brookie rod is 7.5 ft 4/5 wt, and it's on the fast side. I load it with 5 wt line for more open small streams, and 7 wt line for the thickest places.
I did have a 4 wt spool for larger water, and it worked fine, but I typically just don't use that rod on bigger water, so I got rid of the 4 wt line.