Most (but by no means all) of the horses who come here for rehab have had shoes on for much of their working lives and have correspondingly under-developed feet.
Shoes are excellent as a way of squeezing acceptable performance out of less then perfect feet but they don't make feet stronger; if you want your horse to develop stronger feet then the only way to do it is out of shoes.
However, taking the shoes off, while the most visible sign, is only one tiny part in the cog-wheel of strong feet and taking the shoes off a horse on a poor diet will dramatically highlight the problems that previously were minimised by the shoes.
Recently someone contacted me about a horse they had just bought, which was barefoot, and they wanted to know how best to keep it that way; I sent some advice on feeding as of course anyone with barefoot horses would. A week later I heard that they had shod the horse because although he was working well he was feeling his feet on tough ground and their farrier advised shoeing, as of course any farrier would!
Two different ways of dealing with the same problem - either mask the footiness by using a shoe or solve the footiness by tweaking the diet. Its up to you, and it all depends what you want in the long term.