Salamun Alaikum,
The particular translation of the phrase is a good rendition in my personal humble opinion.
The context is important. The Aad community were simply being reminded that after Prophet Noah they too were given authority and given vicegerancy (I know a lot of translators translate it as 'successors' - but there is no reason why in my humble opinion that the context demands this exclusive interpretation).
The phrase 'wazadakum fi khalqi' (increased you in creation) does seem to infer some kind of excellence of being. This could be a reference to a number of things such as an enhancement in power (in status, authority, prosperity / wealth, honour and strength), multiplication of their numbers, natural faculties - including intellectual, knowledge, physiological strength, stature or might.
This phrase should not be thought of as being limited to the interpretation that it only means 'physically large' human beings as is often the case in Muslim thought.
I hope that helps, God willing.
Joseph.