It's a bit sudden for us. I did not find any prior announcement or discussion (before 16.04 release) that Canonical would drop i386 images right after 16.04 LTS.
We, at Medo, use Compaq 610 and Dell Vostro (core2duo). Although they are capable of running 64 bit software, we use 32 bit images because of memory constraint, they all come with only 2GB RAM. And on some older hardware we run Ubuntu Mate. We are slowly moving into 64 bit computing, but I don't think it will happen before 2018/20.
Our work requires that we stay on latest LTS all the time (and sometime on latest non LTS) and honestly we were hoping that we could go on using i386 at least till 18.04 LTS without upgrading the hardware. I mean I can understand that it can happen after 18.04, but dropping i386 builds right now? Right from 16.10? it's all a bit sudden.
I hope Canonical is considering small organizations like us and analyzing all the options carefully.