I would really appreciate a good design that isn't so painful to work with.

如果这些设计能做得好些，让我不那么痛苦的话，我会非常感激。

At your convenience, I would really appreciate you looking into this matter/issue.

如果可以,我希望你能负责这件事情。

Updated: also, if anyone can tell me how to simplify my code, I would really appreciate that.

更新：还有，如果有人可以告诉我如何简化我的代码，我将非常感谢。

I’m a newcomer here. I would really appreciate it if you could clue me in on the library of the school.

我新来乍到，如果你能给我介绍一下学校的图书馆，我将不胜感激。

BREE: Rex. Seeing that you're the head of this household, I would really appreciate you saying something.

鉴于你是这里的一家之主，如果你能说点什么我将感激不尽。

I would really appreciate meeting up if you can spare the time. Please let me know what suits you best.

如果您能抽出时间，我希望能与你见面，请让我知道您最适合的时间。