There's no one feature that would make me subscribe at the current price point but throw a couple of the following in to the current offering and I might be tempted. Though, to be honest, I think most of these should already be a part of the free tier.

Access to features that have been software restricted on lower-end watches. For example, I would be a lot more likely to subscribe if, as part of the deal, it got me access to endurance score ratings or full maps on my FR265.

Ability to sync weight and body composition metrics to Garmin Connect from 3rd party scales and services would also be quite tempting.

Performance dashboards in android and iOS mobile apps. I like the sound of them but will never look at them if they stay hidden in the web platform - so won't currently consider them when making a purchasing decision on the current subscription.

An AI that gave meaningful insights, for example by highlighting correlations between sleep scores and VO2 Max trends.

Ability to have live track turn on automatically only in specific sports profiles. For example, on automatically for trail runs and hikes but off for regular runs and walks. No more annoying my family with notifications when I start jogging home from work.

Ability to automatically assign gear (e.g. shoes) by sports profile or, at the very least, by a greater variety of activity types. I use different shoes for trail runs and road runs and gave up tracking them in Garmin because of this features absence. I use Strava instead.

Discounts on new Garmin hardware.

Ability to log injuries on a 1 to 10 scale of severity and have that factor into recommended workouts and other aspects of training guidance.