[Banknorris]

This script eliminate the use of #showtooltip:

hooksecurefunc(GameTooltip,"SetAction",function(self,action)
    local action_type,macro_id = GetActionInfo(action)
    if action_type=="macro" then
        local _,_,spell_id = GetMacroSpell(macro_id)
        if spell_id then
            GameTooltip:SetSpellByID(spell_id)
        else
            local _,link = GetMacroItem(macro_id)
            if link then
                local item_id = tonumber(link:match("item:(%d+)"))
                GameTooltip:SetItemByID(item_id)
            end
        end
        GameTooltip:Show()
    end
end)

So a macro like:

#showtooltip
/cast [@focus,harm][]Wind Shear

becomes

/cast [@focus,harm][]Wind Shear

but if you have something like this

#showtooltip Hex
/cast Nature's Swiftness
/cast Hex

you will not get benefit from it, you will still need to use the whole line.