My sushi rice comes out chewy on top, mushy on the bottom
If you believe your burners are getting too hot, you can always try using a taller pot with slightly more water to keep the rice from getting dry on top or crispy.  A larger pot would not work because it would increase the evaporation rate of water from increased surface area, then drying out the rice on top while overcooking the rice on the bottom. A taller but smaller pot would keep more water from evaporating out of the pot and drying out your rice before cooking is finished. 

A smaller diameter pot with a 2:1 ratio of water to rice on the lowest setting would be your best bet for cooking the rice on your stove.  Possibly leave the rice covered for the entire cook time to make it cook more uniformly overall, keeping the steam inside to prevent the top layer of rice from getting crispy.  If the rice is still mushy, washing the rice helps considerably in getting that "mushy" consistency from forming.

If none of that works, you can always use a microwave to cook rice.  I had this issue a few years ago and found that a microwave was more cost efficient than buying a rice cooker since I already owned a microwave.  It isn't a fix for troubleshooting your issues with your stove, but it might save you some of the hassle in cooking rice that isn't satisfying on your stove.