No, it’s actually not. You kind of need someone other than PG13 to defend at a high level. Teague/Monta/Miles have never been known as great defenders, and aren’t likely to become great defenders next season. Turner still has some learning to do before he can get there (if he gets there).
Your “flip or flop” idea is great — and Indiana Pacers are going to… flop. The Pacers lost good defenders at the most important positions (PG, the point of attack, and C, the last line of defence), and replaced them with… not so good defenders. Their defence will suffer. Their offence will probably be a little better just by virtue of being a speedier team that can get up and down the floor. However, not expecting big things because they’re not going to be a great 3-pt shooting team, which is part of what you need to effectively play small ball in the first place — to spread the floor with shooters and open up driving lanes.
So, while it will be interesting to see how all the pieces are going to come together, the preliminary prognosis is that they are going to struggle on defence and stay in the middle of the pack in the Eastern Conference. PG13 is going to have to work very hard both offensively and defensively, because he is the only guy that is a plus on both offense and defense. Unfortunately, he’s not LeBron James good and can’t elevate his team enough to get to the “upper echelon” of the Eastern Conference.