Bastiodon has base defense of 168 and base sp.def of 140. Now consider that swampert only has 90 base defense and Milotic 100 base sp.def, thats quite a big number. Generally most players begin by setting up there teams by sending out walls first. Ryoji, as you've seen in the past is an example of this. Consider also that not a huge pool of pokemon are generally equipped with fighting moves, there are of course a few exceptions though, but there will always be cons to the pokemon you select, none are, a matter of fact, perfect. I generally abuse the former note that teams generally set up first, which explains the use of Stealth rock and Toxic. Take into account that Bastiodon is not an offensive pokemon due to its lack in attack power, which draws me away from the use of rock slide. Protect not only acts as a stalling move, it can also be used to 'preview' the move that the foe uses, and allows me to act accordingly. I saw you used Close combat with protect up, so i withdrew flying type, Skarmory who has 391 defense. Immediately after, I knew overheat would shortly follow, which explains my reasoning for switching to ninetails. Sometimes you have to look beyond the player and their next actions ;P