Honestly, I would look into the chance at trading the bow in for one that fits you.  If it was me, I would always have it in my head that I was shooting a bow that didn't really fit me.  You never know until you ask.  Are you dealing with a local bow shop?  They might be interested in a one-for-one swap +- a little $.

I'm not really sure how much of an affect it will have.  But, I can guess that if you are only drawing a 28" bow to 27", you won't be effectively using all of the available energy.  If you are indeed a 27" draw and are adjusting your draw to 28" for the bow, you may need to refine everything that you are use to doing (anchor, peep height, etc).

Good luck either way!  I've heard great things about that bow!

The only adjustment to a longer draw length that I know of is to let your arms grow some to where it fits.  There is a reason that bows come in different draw lengths and that is to fit the shooter to where he or she doesn't need to alter their shooting style.  So is sounds like a trip to a pro shop to where they can either change out the cams or trade the bow for one that is the proper draw length for you. 

A proper fit for a bow is just as important as say a proper fit for boots.  You can make out with a little shorter draw length, but a too long draw length will affect your consistency and string slap is painful.  I'd vote for trading it in and getting a bow that fits you.  Like a pair of too small boots, it will detract from then enjoyment of your shooting and hunting pleasure.

This may get deleted but go to ArcheryTalk.com.  It is an archery only forum.  I bought a set of cams from there to shorten my draw length on my Hoyt.  Cost me 50 bucks.  Alot of guys there sell everything and there is always a lot of cams up for sale.  Your current string may work if not all you will have to is replace the string for about $100, plus you will get a whole let better strings if you go to a good pro shop.

I agree to look around for a new set up to shorten the draw length.  Have you gone to a bow shop and ask about doing it there?  since your bow is new they may take your stuff in on trade reducing the overall cost to you.

No matter how you proceed, I would recomend getting a bow that fits.