Mass Effect 4 is probably still a few years off. Most of the Mass Effect team is helping Dragon Age: Dreadwolf get off the ground, and BioWare hasn't given any clear signals regarding ME4's release window. Some observers predict the new game might come as soon as next year, though that might be overambitious. The actual release date could still be several years out.
Regardless of when Mass Effect 4 comes out, the game has a lot riding on it. There's been plenty of speculation about game mechanics, story details, which Mass Effect 3 ending is canon, and the game's relationship to Mass Effect: Andromeda. However, one thing that BioWare absolutely cannot neglect is the game's love interests. BioWare will, of course, need to bring its quality character writing to bear in that department, but the studio can't neglect quantity either.
BioWare Romances
It takes a lot of work to overstate how essential Romances are in BioWare RPGs. It would be silly to say that Mass Effect 4 would fail if its love interests weren't up to snuff. However, people would miss them if they weren't there, and Romances play an outsized role in the BioWare fandom. While that might sound strange, it's not surprising given the amount of effort and writing talent the studio puts into its optional love stories.
Rather than simple side quests, BioWare creates characters that players can grow attached to. The writers do their best to make these love interests feel like real people rather than just toys they can manipulate. This has a lot to do with BioWare's focus on character writing but also because the games use romance to create conflict and drama. For example, Shepard's Mass Effect 1 love interest won't appreciate being cheated on in ME2, which will influence their behavior in Mass Effect 3. BioWare's also not afraid to tug at the player's heartstrings, and this can range from sweet moments of emotional intimacy to dramatic displays of self-sacrifice.
BioWare games vary in terms of how many love interests players can choose from. For example, KOTOR, Jade Kingdom, and Mass Effect 1 only had three romances, while Dragon Age: Inquisition and Baldur's Gate: Siege of Dragonspear both had eight. Mass Effect 3 technically holds the record with 15, though mostly because it lets players continue relationships that started in the first two games. However, that won't be possible if Mass Effect 4 features a new protagonist, which seems likely.
Mass Effect 4 Needs More Romances
Mass Effect 4 doesn't necessarily need to break Mass Effect 3's record. However, BioWare should try to include as many full-length romances as possible for a few reasons. First, players just seem to enjoy romancing characters they like, and BioWare should give them more opportunities to do so. Romance subplots can also help expose a character's hidden depths since it lets players see what those characters are like in private moments when they have their emotional guard down.
It also helps diversify the characters and stories that Mass Effect 4 can tell. BioWare has a lot of freedom to decide how its romances play out. As a result, the characters' romance subplots reflect their personality in exciting ways, as players can see in Dragon Age: Inquisition's Romance options. For example, Cassandra has a gruff exterior but a romantic heart and wants someone to sweep her off her feet. Meanwhile, Josephine's love story in DAI is dramatic but relatively chaste, while The Iron Bull's may be the most outwardly sexual in any BioWare game.
The point is that more romances increase Mass Effect 4's storytelling potential. The new game probably won't suffer too much if it only has a small dating pool, and BioWare should never sacrifice quality for quantity. However, BioWare would be passing up big opportunities if it didn't feature more romances in Mass Effect 4.
Mass Effect 4 is in development.