Tosker is much younger, and livelier, than my other two, who in all honesty took to their cardigans and carpet slippers before their middle years
one of the reasons I took on a younger problem rescue cat was in the hopes of shaking them up a bit - and although there has been precious little bonding, Trigger and Tiff both spend more hours awake, go out more, and eat better, than they did before Tosker arrived
life here may not have got better in their eyes, but it sure got more interesting
so I don't think you should only judge whether Dexter was a good idea simply from the lack of negative interaction - aggression is also part of a cat's natural behaviour, and as long as it doesn't get out of hand is fine in my book