My two cents. Ritual prayers/Salat is a mandated act to be done by individuals at specified times. If Quran in Arabic is not read in this salat, then it is not a Quranic Salat. It would be perhaps more appropriate if parts relevant to a particular problem/situation at hand are recited. The problem however is not how much and which part, relevant or otherwise, is recited. The problem as I see is twofold:
First, not knowing the purpose of Salat, as to why one is doing it? What purpose God defined His Salat to achieve for us? What we want to get out of the Salat? Are our purpose of doing Salat and God’s purpose for mandating it aligned?
Second, the lack of clear understanding of the most, oft-repeated chapter 1, as to what it entails. After Eman, this is our pledge to live our lives keeping God’s guidance in front of us under all circumstances. Of course to know God’s guidance one needs to read/understand the book for at least those parts which are not clear to us. Vast majority of commands are very clear to both Arabs and non-Arabs, for example, speaking truth, doing justice, respecting other’s rights, etc. There may hardly be just a few commands needing expert opinions and understandings. So the language is not a barrier for most part.
These two parts when fused together harmoniously can strengthen one’s Eman, thereby making the person to be steadfast in following God’s commands. Muslims offer Salat in all circumstances: when victorious, when defeated, when happy, when angry, so on and so forth, for God’s remembrance is supreme over everything else, and it refocuses our attention away from our success and failures back to God.