Fox (SSBB)/Down special
Fox's Reflector, known informally as a shine, can reflect projectiles that are fired on Fox back at the opponent. Fox can also use the reflector as a direct attack, knocking opponents on a semi-spike trajectory with low knockback.
The move was regarded as the best move in all of Melee due to it being an incredibly versatile attack for many reasons being usable in almost any situation. As a result, the move was significantly nerfed. The move can no longer be jump canceled which removes much of its followup potential. The move suffers from the general changes to Brawl's mechanics but unlike most moves which suffer either from the introduction of hitstun canceling, the universally decreased falling speeds or both, Reflector's main downfall was the removal of wavedashing. The main thing which made the shine as amazing as it was in Melee was Fox's ability to wavedash which allowed him to quickly get back on the ground and perform another Shine which gave the move amazing shield pressure potential and even the potential to infinite a majority of the cast. Naturally, the removal of wavedashing alone harms the move's utility. Even if the move were hypothetically jump cancelable in Brawl, it would still be a significantly less oppressive move as Fox would not be able to get back on the ground anywhere near as quickly to perform another Shine. The move also saw some other more direct nerfs. It has increased startup lag (now coming out on frame 3 rather than frame 1), it deals slightly less damage on aerial opponents and it launches opponents at a slightly higher angle which hinders the move in multiple ways. It makes the move less effective as an edgeguarding tool, it makes SDIing the move easier especially with its higher hitlag and it prevents the move from locking opponents which it otherwise would have gained the ability to do.
Despite these nerfs, Reflector has actually seen some buffs which still make it a useful move. The move's hitbox has a slightly longer duration and its intangibility has increased making it more effective at breaking out of combos despite its increased startup lag. If Fox does not hold the move, it also has considerably lower ending lag. On the ground, this allows the move to have at least some followup potential particularly at the wall where the move still has 0-death potential (although this can be avoided with SDI) and in the air, this gives the move extremely strong stalling capabilities. The move no longer has set knockback instead have high base knockback but low knockback scaling. This prevents the move from knocking down lighter characters at lower percents removing one of the few limitations it had in Melee (although this also means that it now knocks down heavier characters at higher percents) and it make shine spikes more effective at higher percents. Fox can also now roll or spot dodge if he reflects a projectile.
Overall while being a farcry from its Melee counterpart, Reflector is still a useful move in its own right.