No. Because then you'll likely have more than 1 rangefinder per ship, and we don't want that. Give the rangefinder and the spyglasses to the crew mates you trust to use them responsibly. Don't dumb it down. Rangefinder should be a bonus for crews who are smart enough to use it.
I really don't see why this would make people take more than 1 rangefinder per ship. Also I don't see why that would be a bad thing if they did - what if the gunner was the only person with a spyglass and both engineers had range finders - the gunner is the person with the most free time to spot ships I think it would be pretty cool if people played like this.
Captains get this ability
for free anyway, in the latest patch captain mark even shows where the ship is off screen with a floating arrow indicator! (OP OP) All it would do is let you point out the location of the ship to your own crew (teamwork required) for them to spot it which shows its location to the rest of the team (teamwork result). Note the ship will not appear on the map if you mark an unspotted ship with rangefinder, the ship will only be rangefinder marked for a few seconds, and it will not appear to the ally ship at all.
I don't think this would "dumb it down" (what great powerful advanced effect do you think the range finder brings, even with my suggested changes?) but only make it appealing to the crews that want to use it. I know for a fact my team would ignore the rangefinder if it left a crew member without the ability to mark a ship to other players on the team, no matter what information it showed about enemy ships. (this is the biggest reason it's bad to take a rangefinder currently!) Are we too dumb to use the range finder, or smart enough to realize it's crap if it takes away a crew members ability to spot at all?
Spotting position is just too important and not having it at all on one player is very bad - one player spotting a ship can have a serious effect on the outcome of the battle, just think how many times that one player on your team spotted that metamidion right behind you and saved your ass. (I can think of a veteran player who thinks spotting is so important that he would always take spyglass as pilot before they added the captain mark ability)