Well there is also the fact that this doesn't seem to be a global problem (since my Note 2 on 4.4.2 doesn't have this double space problem using the Samsung keyboard). Which means it could be a carrier firmware problem since they do tinker around the firmware before releasing it to their subscribers. Contract acquired phones tend to get all the bugs because of this carrier interference on the firmwares (locking them, adding and changing stuff in the system partition, etc). Although for what it's worth, i have received 3 updates since November. None of these changed the Android version and the summary only says bug fixes. Are you saying you received ni updates in the same period?
I won't tell you to not go for Apple, it's your choice, and for all the flak they get from Android users, they have good devices. Just remember any app you bought on Android needs to be bought again. Devs don't usually transfer licenses. However you won't have to contend with the carrier interference and bloatware.
As far as I can tell, the update for the Note 2 should roll out by March. However, your carrier may choose to delay the update or tp not release it at all. The phones which aren't tied to carriers are sure tl get updates though.