For Etihad that's actually a better offer than most get - typically they tend to offer only 5,000 Etihad Guest points for poor performance, if you manage to get anyone to respond/care.

Etihad frequently suffers delays into/out of Heathrow - it is a rarity if flights are on time and knock-on effects are common occurrences. Etihad is generally poor at managing flight disruptions and ground staff competency is very variable (with fob offs and false information often occurring).

Sure 20,000 Etihad Guest points is really not anything more than sop (a token gesture) but it's better than it's usual response (or lack there of). I highly doubt the chance of anything more appropriate being provided.