The Spyglass is very useful new item, however it could be even better! My suggestion is that it can have a maximum of 1 enchantment, these would be rare and would only be found in dungeons or traded with villagers. (I have taken and modified some ideas from the community and made my own, also I am bad with names, so take that with a grain of Sault)
Scoped lens - makes it so that not only can you now see further, but you can also zoom in and out
Revealing - temporarily gives mobs the glowing effect when looked at
Sniper's dream - like a scope, it would give a general idea of how high to point depending on the distance of shot you want to make (would work better if it was conbined with a crossbow, either directly by crafting, or indirectly by dual wielding)
Night explorer - when looking through the Spyglass it would be like having night vision
Fire lense - when in daylight, looking at a mob for a long time would cause it to set fire (rarest enchantment), for balance, it can only be used at midday when the sun is strongest
On top of this you could also find Spyglasses with curses on sunken ships, like giving nausea effect, etc...