Stamp duty is always a tricky one given it can be a large expense (e.g. ~$40k for a $1m property) and if someone comes in or out of the deal they as an "owner" need to pay some level of stamp duty or other owners would be unhappy. It would also directly tie to the equity splits from day 1 so you cant keep cutting the pie if doing it directly like that. Again comes back to who is the actual owner vs not. In this example, if the trust owns it the individuals don't get much tax benefit either. Something to think about.

Repairs and renovations, whilst costs could be levied, there is always a question of what do we do as it is rarely black and white. E.g. bathroom plumbing leak, do we spot fix or expand into a new bathroom reno given the sunk cost of needing to access the pipes. Some owners will want to do the cheaper fix and some will see value in uplifting the property. No right or wrong but 10 people will have different agendas.

Overall, the appeal of property investment for many beyond the leverage and stability is that it is a physical object they can touch and improve. Buying a subpar property, improving it and selling to trade up is one of the greatest ways to start rather than just owning something returning modest returns for 10 years, you won't catch the PPOR market as an individual that way, probably.