So the longer the amortization, the more aggressive a landlord can be with rent. If your business is in a shopping center and relies on an anchor tenant, that anchor's leaving could have a dramatic impact on traffic to your store. You could negotiate a provision to change your lease if this happens. The landlord understands, but at the same time they have a commitment to meet obligations of their own. There is a going dark clause you can negotiate in a lease to address this situation.
Landlords are generally happy to have tenants do improvements.
So if you can do the improvements inexpensively, you could use that to your advantage. In fact it happened a lot in the dotcom industry. They had a lot of money but no credit history, so many did improvements in exchange for a better rate. Every Real Estate Lease Should Address Before You Sign .