I'm not sure about others; myself, although I'm a long-time Ferrari fan (since 1999), even if Mercedes is dominating, as long as the racing is close and many overtakings and uncertain strategies, I'll consider the race isn't boring. But like football matches, some are snoozefest.
Even if I don't want to see Lewis win another WDC, I've to admit he is one of the greats, especially in qualifying. This season, I rather see Valtteri Bottas win WDC if Ferrari & Red Bull can't catch up.
Asides from a top team, usually I'll support another mid-field team and maybe an underdog team, depending on the driver or manufacturer. E.g. this season I like to see Renault to be best of the rest, coz maybe due to Daniel Alvocado. Alfa Romeo, I think can categorize as underdog, not really mid-field team but I like to see Kimi scoring points. So, if the race leader is way ahead, the TV director usually will cut to closer racing in the mid-fields. Plus, the commentators must be good.
Hoping for better closer racing after 2021 major regulation changes.
Martin Brundle is rubbish and biased, Paul Di Resta gives better commentary.