Choosing to play with 28mm has its disadvantages and advantages without a doubt. When I last built and played with 25mm historicals, foot were 50 cents, mounted troops were $1 and artillery were around $5 for a gun and 3 crew. (note these are NZ prices from the mid eighties so that tells you just how long it has been)
Back then I was dealing with a 1500 point Renaissance (Gush WRG) Persian army that featured around 70 cavalry, 3 guns and 130 foot., not exactly small or easy to transport (no plastics back than), and the selection of manufacturers was very limited.
If I was going to work with 28mm, I wanted something that wouldn't inveigle me into an ever-expanding arms race of miniatures purchases (hence Sharp Practice and FIW as opposed to British Grenadier and AWI) and also would meet the Goldilocks principle of wargaming - not too big to wear me out from painting fatigue and pressure to complete, and not so small as to seem somewhat half-arsed or paltry.
I did consider AWI with the plastics (TBH, I will almost certainly go down that road in a couple of years anyway - I know my foibles all too well) but I didn't want top faff about with a large amount of assembly of miniatures (one of the reasons my CoC 28mm WW2 stuff is still sitting in boxes). I appreciate the heft of metal, particularly when handling individually based figures and dealing with casualty removal/sabots.
Another reason for going with metal is that as I am re-learning how to paint in effect, I'll almost certainly be stripping my initial attempts once I've reached a standard I'm happy with.
The real clincher is my eyesight - brought home to me with a vengeance in the last 4 months. the thought of trying to paint even twenty 15/18mm figures fills me with dread. I've just had to move to a combination of three different pairs of glasses - Distance, Reading and PC/Office work - after 40 odd years of a single catch all prescription.
One of the reasons I stopped painting and modelling was that I was getting severe headaches within half an hour of starting a painting session which sucked all the joy out of creative endeavours. So moving to larger scale was always going to be on the cards.
I'm not going to try and create masterpieces in 28mm, so decent table top standard will suit me down to the ground and I'm happy to do without painting eyes or details that can't be seen without picking up the figures anyway.