I dont understand how the Svara version of Rav Yehoshua Ben Levi makes sense. According to his Svara, Smichas Geula LeTefillah is only necessary by morning because that is the main Geulah. But still, that does not tell us a reason why he specifically would want Shemoneh Esrei before Shema! It only tells us that the order does not matter
Note that the Gemara presents Rebbi Yehoshua ben Levi's opinion with the words, "Tefilos b'Emtza Tiknum." This suggests that the Chachamim wanted us to begin the day and to end it with Kabalas Ol Malchus Shamayim, which is possible according to the view of Rebbi Yehoshua ben Levi but not according to Rebbi Yochanan, as the Gemara explains.