Need help for my croton

Too much sun

I'd guess that it's MORE than rootbound in that pot after all this time. Time for you to either plant it in the yard or get a new one to keep in a pot.

It is not to much sun.....Repot in fresh soil in the next size pot.When repotting, gently pull the baby roots down and snip the excess,cut the large roots,add some soil in the bottom of the pot,place the plant and fill with the remaining soil. As a suggestion move to partial shade until you notice the plant recuperating then move back to full sun. Keep moist not saturated.

Anyone in agreement on cutting it back?

http://homeguides.sfgate.com/repot-crotons-35983.html

Once it's repotted, wait until a dormant period or until it has recovered from the stress and then cut back on the tops of maybe ten percent of your stems. See what the reaction is. It should start sending out new growth shoots along the branches. We had crotons growing outside in South Florida and I can recall my Dad pruning them back when they'd get out of hand. Just don't overdo!

i would make sure the new pot has plenty of drainage (pebbles in bottom), and like someone said put in protected area (not so much sun) until it has new growth established.

To get a plant to bush out, you pinch the terminal apex pair of leaves at the top of each stem when they first appear, this causes the lateral buds to bloom sending out new growth.