Yes Canon is there with the largest exhibition area. It is not crowded as one might expect. Of course M5 and 5d MkIV are well visited. I was now five days at the photokina and it seamed to me, that all the knew cameras at all manufacturers were t big hit. It was different today on Saturday with more non professional visitors.
I would say going to photokina only because of new allready known bodies and lenses makes no sense.
You will need about one day to look at all the exhibitions. You will need at least another day to be at the main events with all the photographers but be aware that most of them are talking in German.
For me very interesting were the new developments on studio and outdoor flashes. Another part of the exhibition you should not miss is everything about printing. Looking and feeling all the fine art papers and talking about there possibilities is worth a whole day, even if you never printed really good pictures at home.
It is a pity that Canon Europe decided to show no Beamer.
These are a view impressions from myself.