Q:
Alts, leveling, and the faraway 80.
A:
As Fluffball said, GW2 is very, very alt friendly. And having multiple classes you know and can play well can be very useful in group content (both pve and pvp). So, if you want to take a break from your engi, feel free to make something new. Pretty much every class (with maybe the exception of an elementalist) will be less key-combo intense.
GW is extremely alt friendly. I would encourage you to make a lot more than 1 alt, even.
There also is basically nothing but a time investment for leveling characters. Your karma for getting appropriate level gear at heart vendors is account-wide (as are all currencies.)
If you were closer to to 80 I would say push through it but at lvl 24 if your not feeling try out playing a different class.
Do what you like to do. There is no such thing as “acceptable” or “unacceptable” in GW2.
The only reason to rush to lvl 80 is if you’re eager to do the “endgame” content (fractals, raids, HoT expansion map…).
Also, if you’re not F2P, and log in daily, you will acquire 10-16 “tomes of knowledge” per month, each of which gives a free level up.