Roses have leaves. I have about a dozen different roses on my body and they all have leaves. Guarantee you that a rose tattoo without leaves would look unfinished.
Don't worry about what it looks like when you raise your arm. Seriously, a tattoo is on a living, bendy, moving part of your body.
And my motto, go big or go home. It's a great size and you can't tell that it is a coverup which is the primary thing. Your artist was right.
I know this is hard but you need to try to get out of your head. It's a good tattoo!