I had to google to be sure, but aluminum in deodorants is actually there as an antiperspirant; its in the form of metal salts intended to block up sweat glands to keep your underarms more dry. (the odor that bothers people is actually bacteria living on your skin that consumes the sweat, dead skin.. and probably something else that I'm forgetting about). so the 3 main ways to attack bodily odors are to kill off the bacteria (can have some downsides), block up sweat glands (seems like a generally not great plan to me, but others may feel differently) or use some masking agent (the de-odor part of deodorant). as far as why you're detecting scent more now, I'd guess it has to do with how your skin reacts with new products vs. the older ones and/or the no aluminum one may have been a better general masking agent since it didn't have any antiperspirant, pore blocking metal salts to try to help.
