Should The Seller Replace Hail Damaged Shingles?

[Dale Porter]

This will be our primary residence. We are first time home buyers. The house is in very good condition overall.

 It's a 15 y/o house with architectural shingles. The inspector noted repair/replace hail damage to the shingles and some cracked boots on the plumbing vents. Sellers had estimates and all said the roof has 5-10 yrs left. Sellers offered to replace boots and replace the damaged shingles.  We are getting the place a tad below appraised value (<1%) and about half of our closing costs paid by the seller.   

Is it better to replace some shingles or will that make the roof look (or perform) wonky? 

Is it a bad idea to buy a house knowing it has "hail damage" and 5-10 years left on the roof? (we like the house and location)