As someone who graduated with a Bachelor of Music in Composition degree in 2006 and hasn't done anything with it since, you might not want to take what I have to say as gospel.

I don't think any studies we ever do are completely wasted, though; whether you continue with your current studies or not, you'll have learnt things and had experiences in this time that you wouldn't have got anywhere else, and I think that's worth something, even if you do ultimately decide to take a different path.
The main reason I wanted to respond to this was to point out that you don't need to be a piano virtuoso in order to compose and arrange, although admittedly people from a piano background do seem to have a more native understanding of harmony.
I never really bothered picking up anything more than basic keyboard skills, and played trombone for eight years before studying composition at university. And even though I haven't actually done anything with my music degree, my lack of piano-ness didn't prevent me from composing and arranging.
I'm not saying piano should be avoided, I just don't think all composers/arrangers absolutely must be fluent in it, although keyboard skills may come in handy.
Not sure if this helped or not, but I just thought I'd jump in by pointing out even those of us who don't play piano are equally capable at composing and arranging as piano-based musicians, so you don't need to feel as though you absolutely must learn piano in order to become a composer/arranger.
