Edit: I suspect Keith (above) probably has the better read on this. I don't have a proper, pointed text with me at this time.
I don't have all my Hebrew assets at hand, but I'll tell you what it looks like to me.
The basic issue is "translational," which is to say, the rendering into English is partly dependent on what the translator(s) believe is the
sense of the Hebrew construction.
Strictly speaking, there is no future "tense" in Hebrew, as for example Greek has a particular tense with its own form. The future idea is typically found in Hebrew when a imperfect form is used without a "vav" (meaning 'and') preformative particle.
At a glance, it looks to me like the majority of the verb-forms in the first few vv are imperfects, without the vav. So, the KJV translators render them in the most common sense, that is "future."
But that's not the only way the words can be understood. If the Psalm is more of a "prayer," then the sense of the words in the imperfect can also be rendered as "petionary," that is "may it come to be so."
The thing to remember is that what is expressed is not instantiated in history, it has not (yet) come to be in the concrete sense of reality (from the standpoint of the original human author). If one takes the imperfect expressions as prophetic or promissory of God, then the future tense is just fine for English. But, a very similar sense may be had by way of prayer. Thus, we pray in the Lord's Prayer, "Thy kingdom come, Thy will be done." We know it will be so, by divine promise.
