No, definitely not. E+ (and only UA offers Economy Plus) is totally different from BA's WT+. UA's E+ consists of some rows of Economy seats with increased seat pitch. It is not an extra cabin. BA's WT+ is in an extra cabin, has seats that are wider, have more recline and more pitch. Another difference is that UA's E+ can be used by travellers paying Y, B and M fares plus all travellers holding *G or *S status. WT+ is therefor a totally different product from E+ (as is SK's Economy Flex).