Sorin, Imperious Bloodlord is without doubt one of the most interesting cards to come out of Core 2020. Its potential is high in Standard – at least during the short window of opportunity before the Fall 2019 rotation. Vampire tribal Commander players and Oathbreaker pioneers probably already have the card on their wish list and eventually, the card may be broken in less casual non-rotating formats.
In 2018, a year before the printing of Sorin, Imperious Bloodlord, about 15 planeswalkers existed with a converted cost of three mana or less. Not even one had a casting cost that included less than two color-specific pips (mana symbols). This of course changed drastically due to the massive influx of planeswalkers with War of the Spark (April 2019). By the time of Sorin's release in July 2019, twice as many planeswalkers were available at CMC 3 or less and eight of those required only one pip.
This saturation may initially have led some players to overlook or even dismiss the new printing of the Bloodlord as just another cheap planeswalker with a set of somewhat "meh" abilities. Moreover, reading those three abilities may have caused a few more players to further pass on the latest incarnation of the former prisoner in a rock as all three are primarily tribal, bound to the vampire tribe.
Not that those abilities are bad in a tribal Vampire deck. Both two +1 abilities work well with classic vampire strategies associated with life gain and the aristocratic style of sacrificing cheap creatures for various benefits. It is, however, the -3 ability that should make everybody take notice. Entering the battlefield with four loyalty makes this "ultimate" something that you can use straight up after resolving Sorin. You even get to keep him in play afterwards.
Straight up at 2B, which is easily available to players on turn one in some formats (or at the very least, turn three), you get to put any vampire (provided that it's legal in that format) into play with a chance of giving it lifelink, deathtouch, and a +1/+1 counter the following turn. In Oathbreaker where players choose a planeswalker as their "commander" (called the "oathbreaker" in the format’s terminology) plus a signature instant or sorcery spell, Sorin, Imperious Bloodlord plus Demonic Tutor lets you put any mono black vampire or black/colorless changeling into play no later than turn three and even as early as turn one with the right starting hand.
Given the selection of vampires at the time of M20’s release, Sorin, Imperious Bloodlord may not yet be a card fit for Modern or Legacy. But as the card pool grows, this may change very suddenly. When the Bloodlord was unleashed upon the game, a total of 235 vampires were available with 208 legal in Modern and 66 available to Standard players. Memes combining the card with Arcane Adaptation and Emrakul, the Aeons Torn aside, what may eventually make Sorin a broken card in more powerful formats would be the printing of another vampire of equal power to, say, Griselbrand. With Sorin, Imperious Bloodlord printed, no mana cost will ever be too much to play any overpowered vampire because in the end, the mana cost will just be 2B.
Between the pre-release and release of Core 2020 (July 2019), prices for the mythic planeswalker have dropped considerably from around 20,00 € to 10,00 €. However, if the card eventually sees serious play in Standard, then it may rise again. Over time, the demand from Commander players will likely keep the price at least at its current level with the prospect of price spikes depending on reprints and future vampire cards.