Indeed. Summer trains are very busy on the route. Last summer I took a service to Machynlleth that was full and standing from Llandecwyn, mainly due to hikers, activity groups and other tourist traffic. Talsarnau is a decent sized village in its own right and Llanbedr, Dyffryn Ardudwy and Talybont all provide a fair amount of traffic. Morfa Mawddach is also popular with people parking and travelling to/from Barmouth (Its a nice walk over the bridge though) - Llwyngwril is a decent sized village in its own right and Penhelig is closest to most of Aberdovey than Aberdovey is.
Even then the lesser used request stops still provide local traffic, and schools traffic outside of summer. A summer hourly service would be a great benefit to the line. So turnarounds aren’t too tight, you could probably get away at turning around the extras at Dovey Junction (connecting with the Aber service) if train crew permits, or Porthmadog/Criccieth northbound. Running hourly would be possible with current infrastructure but not much scope for if things go wrong.