As a preface, let me say that I am not arguing because I want to argue, I am arguing because we have a difference of opinion on whether
Arcane Savant is a good design. Just because I don't agree with your opinion doesn't mean I don't read what you write.
If someone wants to define what is a good and what is a bad design philosophy you are allowed to lead with that before jumping to conclusions. We can argue that before we go straight to stating that one of the simplest cards in the last 8 years of Magic is a badly designed.
In my opinion, a good design respects both spoken and unspoken design restrictions, including adhering to the color pie, and adhering to expected power level in relation to both mana value and rarity of the card. A good design that breaks any of these restrictions should, in my opinion, do so at a cost. For example,
Elvish Piper can put any creature onto the battlefield, including non-green ones that you could not normally cast in a monogreen deck and really expensive ones that cost way more mana than you would have available on the turn you can first activate the Piper. What's the cost here? Well, for one, you need to let a fragile 2/2 sit out on the battlefield for a turn before you get to do its thing, but also, you need to include the off-color card in your deck and draw both it and the Piper. Likewise,
Arcane Savant cheats both mana cost and color pie. What's the cost? Well, you need to draft the off-color spell you want to cheat out. That's it. It doesn't ask you to include the card to be cheated out in your deck, you don't have to draw it, the Savant doesn't need to sit on the battlefield for a while, it just does its thing when you cast it. In my opinion, there aren't enough drawbacks for such a powerful reward, making it, again in my opinion, a bad design. In other words, I don't think it's a bad design because it is good at cheating, I think it is a bad design because it is cheating at no cost to the composition of your deck.
If you still disagree, that's okay, we can agree to disagree. I don't think there is a need to be angry just because we have different opinions. After all, that is exactly why we come to this forum, to discuss about all things Magic.