I would say that it has been far from stagnant but would agree that the other areas mentioned have developed faster perhaps but arguably from a lower starting point (unless you go back 15 years or so but there has been an utter transformation everywhere around since then).
For recent developments, the Brockley Rise stretch has an upcycled furniture shop, antique shop, a health practitioner and a tanning salon. Le Querce has an improved exterior. Honor Oak Park has a new Turkish restaurant and two art related spaces. Mamma Dough on the corner is getting a face lift, a new cafe is coming soon and potentially a new bar too depending on what the Appeal Inspector says.
Don’t forget that Forest Hill Road is also developing nicely with a vape shop, Turkish baths, craft beer pub, new cafe and grocer/juice bar.
Quite a lot going on in Honor Oak!