I have been looking into this kind of issue recently in anticipation of purchasing another rental. Many years ago I inherited some rentals with their tenants. The ones that had been there the longest were paying the least rent and had never really been screened. Hind sight is 20/20. We should have turned them as soon as we could. Those properties were in the worst condition.
In Kansas, under the Landlord-tenant act, it appears that you do have to honor the remainder of the term of the lease. However, you can put them on notice that their rent will go up when their lease is done.
Horror story:
We finally had our last inherited tenant move out in 2015, if you can call it moving. His family put him in a nursing home, leaving all his crap behind. They did not tell us, we had to go through the eviction process to legally take possession. We wanted to cry or burn it down. But we flipped it to ourselves. Had to refinance another property to get funds going, because we had to pretty much rebuild it. Before we finished we were able to refinance it so we had the funds, just barely. We probably over improved this 920sqf house, but instead of getting $850.00/mo, (like the non-updated rentals in the neighborhood) we are getting $1335.00/mo. It is beautiful. We over improved, but we are very proud of it. The extra upgrades totaled only about an extra $11,000.00, but are bringing in an extra $500/mo. If we downsize we may move there. We were only hoping for $1200.00/mo, but upped it. You can always come down. You won't get what you don't ask for.
After our experiences, I say go ahead and ask for what you want when the lease expires. If you low ball now, you will never make up the loss with these tenants. You will have to wait another 20 years while they suck away your dreams.