O.K. I know. The text is pretty crazy. Let's break this design, and I'll get to a part where you might be going, "You can't do that; it's against the rules."
Name - since I haven't read the story, I wouldn't know whether Eldrazi Monument is something that exists in the storyline of great significance. It seems like it, and the art could have been created of this very significant part of the story in mind - thus, I'm not touching the name.
Mana cost - Since the original design was priced at 5 with a drawback and pumped its creatures with a +1/+1 along with other benefits, my design would be costed accordingly. One, I don't have any drawbacks. That should increase my cost by at least 1. A 6 converted mana cost should be enough, but to be on the safe side, I decided on 7. Turn 7 and beyond is pretty much the area where games might already have a winner decided.
Increasing numbers by 1 - Why did I decide this? Because if this is a monument to the Eldrazi, I wanted to make sure it could help all Eldrazi. But I couldn't just say "colorless creatures," because this card appears in Zendikar block! What did all the Eldrazi have in common? Annihilator. And all the annihilator abilities have a number. Thus, I had the direction. Then I shaped the effect into something that is applicable for any deck running creatures.
The templating - Overload on the Izzet cards mention "change its text by." So, I figured I needed to include that. Cards that change color words, for instance, also say "change the text of SOMETHING by replacing all instances blah blah blah."
Next, there was the problem of numbers. There are two different formats for numbers within the text of a Magic card: digit and word. "+3/+3" and "three" are examples of each, respectively. So, how was I supposed to prevent players from playing this card incorrectly when it comes to digits and words? I decided the answer was to be inclusive of both formats of printed numbers.
Now, I'm not exactly sure how much I broke something within Magic by doing this, but one good thing is that this only affects creature cards - well, yes, the most prominent card type. But here it is.