It seems to me that the core of your proposal is much similar to what we discussed in
(correct me if I am wrong! 
)
I signal that @georgehrke (calendar app developer) expressed his perplexity in including resources in calendar
Concerning the chat app there is already a lot of work ongoing in the spreed app
Concerning the doodle like functionality I remember a Polls ownCloud app but it seems it is not ported. You could test if this works. Eventually the porting of this app could be a minor programming task (I am guessing…)
Concerning the unified view between calendar, chat, polls and other things in the event management, I guess this will benefit a lot from the ongoing work in the tagging support. I would appreciate a lot this possibility but this is a lot of work also in the “usability department” (@jan… ).
Hope this helps.