There is both dynamic accenting and rhythmic pulsing in fills. As said, you want to be able to play things perfectly evenly, and then be able to swing or place accents however you want. Any given tune or group of musicians may stick accents in some place, and you should be able to go with it, without having to think. Tall order I know. Something I aspire to as I know drummers who can do this and love how they can both follow and contribute to the music this way.
I'm surprised this doesn't go without saying, but of course you want to be able to have full control over the accenting; and that doesn't just go for rolls. If you can't accent any note you want, at will and hopefully for the music's sake, you should want to keep at it.
To be able to play your rudiments to sound exactly the same on each hit is a great thing. You want to be able to have that control. But of course, there are times when accenting is called for. It really just depends on the situation.
So I've always tried to do my rolls as consistently as possible, with each and every stroke sounding equal. However..
I was just playing along to Foo Fighters, Everlong, when I noticed that Taylor Hawkins accents his rolls on the 2 and the 4 sometimes, and other times on each quarter note.
Should I aim to be able to pulse the roll wherever I feel I need it? Does an accented roll sound better with the 1,2,3 and 4 emphasis compared to a dynamically consistent roll? Does this applie to single stroke, double stroke and paradiddle 'rolls'.
I think I know what the answer will be, but I'd like to hear others opinions on this.