It's normal for the hildon-input-method to come back as it's a system daemon (a process meant to run in the background and provide services), not a normal process. However, if it's coming back and still at like 90% of your CPU, then there is something fundamentally wrong with your input-method daemon. A re-flash would probably be the easiest way to fix this for good in that case, so make a backup, flash, and then restore backup.