I don't mind the crap shoot aspect but it is one of the more pointless Wonder/Rites in game. Currently, Getting the Master of Magic victory is a joke. It is far and away the easiest to win with- and that is even without exploiting the Dispel spell.
If Kael and Co. removed the cheap mechanic of allowing players to dispel nodes that have already been used to secure a specific tower (by say, making sure that a Tower Of Mastery can't be built unless you OWN a single node of every type on top of all 4 minor towers) then Rite of Ogma would suddenly become a worthwhile endeavor.
Take it a step further. Under those guidelines, make it so manas acquired by trade were likewise not counted towards Tower of Mastery. Then, set up Rite of O to either create nodes all in your borders or a fixed % of said nodes, and then you would not only make it more relevant but also increase the difficulty of the victory in comparison to the others.
I am out of breath.
Its not an exploit.
Kael has introduced Metamagic 2 explicitly to make this kind of victory easier and to make the nodes really valuable points of interest instead just a sidenote. (Kael gave his assesment on the quality of spells from his design perspective. And Dispell Magic was way up there i believe. So stopping to call it broken might be a nice idea to come to a reasonable discussion rather then crying foul all the time...

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Also what you say only holds true on large and huge maps at gamespeeds normal and slower.
On normal size and below (the smaller it gets the harder its relatively to the other options and! in terms of direct difficulty.) its far from the easiest.
And in the time where you really needed any node it was borderline impossible to achieve this kind of victory without deliberately delaying another kind of victory-condition like domination.
But if you care to look around in the strategy-subforums a bit you'll likely notice that many experienced players rather aim for military victories and achieve them (in the higher difficulties) in a number of turns where the builder-victories are a burden to get at best and impossible at worst. (around Turn 200 - 300 normal speed is nigh impossible - rather hard to do by any of the builder victories but not seldomly seen by the military ones...)
The Altar is not that much harder if you know what you are doing (its a bit harder to set up well. But not really that much harder in terms of resources and it uses similar techs... Only theocracy is really mandatory. And basically anyone has access to that civic later in the game.
Also the potential Drawback of Wars is far less severe. Lets see what the AI will do once its really worked...)
Culture is similar in that the effort is doable. But there the problem is combination of needed planning basically right from the start and much more focus needed to achieve. But its far easier than it looks on first impression.
I'm much more fond of the builder-style victories myself. But there is no real problem with those by a wide margin.
Take multiplayer as a reference here (if with quite many flaws, i must admit). There it hardly ever seems to be achieved by a builder route.
The game is actually supposed to be finished not by a time victory but by one of the conditions.
And given that at least some players actually wrap up games the team accomplished the goal of making them interesting enough. Make them harder and barely anyone will ever see them through. Thats hardly what they should be designed for imo. But that's just my 2 €Cents...
So a big no for that idea from my part.
In terms of the ritual a combination of the following might bring it up to interest.
either / and:
a) put it on an earlier tech
b) make it cheaper
c) make it repeatable
d) make it a "national" ritual instead of a world one. So in late-game the big civs standing all profit from it at a time in gameplay where its most "needed". (and i heard that the AI is rather fond of rituals now. So that shouldn't be to much of a concern.)
Otherwise its not worth the spot i must agree (rather put something else interesting in there. Late-game-wonders and Rituals are the 2 things i still think the mod is a bit thin on really...).
Cutting it currently seems a real option sadly, as cool as the concept sounds in itself on paper. I strongly doubt there are no better ideas in the pipeline worth taking its place...