The first thing I would do is contact other residents – tenants as well as owners – and ask them if they have experienced any of these issues. maybe a leaflet unde their doors or in their mailbox. You don’t have to make it accusatory – just a simple question. If more than one person has the problem it can’t be wear and tear.
As for the developer saying they will fix things once and for all, I wouls simply reply that they have responsibilities set out by the SSMA which are not subject to modification by their arbitrary decisions on how often they will fix things. They have a duty to repair or replace lot and common property that is defective and is reported within the time limits set out in the Act and the Regulations – end of story.
If you think it will come to the point where you wish to appoint a lawyer, I would get a group of owners together to fund that in the first instance.