Editing Dungeons & Dragons 5th Edition (section)

===Companions and Summons===
In previous editions, classes who could summon other monsters or acquire companions as part of progression were frequently seen and noted as "difficult."  On the one hand, incredibly powerful and potentially encounter-altering, with the druid's animal companion often seen as a ''superior'' replacement to the entire fighter class.  On the other hand, bothersome and number-crunchy, with games slowing down as players have to keep track of two different characters or scrounge through Monster Manuals for summons.

To that end, both options were messily clobbered into bloody dust with the nerf bat.  Unfortunately, well...  let's start from the very beginning

The Beastmaster ranger is by far the most infamous example here, with a barely-scaling animal companion that the ranger needs to use his own actions to let move and attack, and which will, according to the RAW, derpily stand around doing nothing if the ranger falls down dying.  Already seen as one of the weakest PC options in the game (before the coming of the Revised Ranger), the beastmaster archetype makes it even weaker, since ''all'' its archetype benefits are devoted to making its animal companion marginally less terrible. It wasn't until the November 2019 UA (and eventually published in Tasha's Cauldron of Everything) where these companions got actually viable options via a set of special spirit companions. Each of them comes with the ability to attack via a bonus action by default, you have only three options for these companions (Land for charging, Sea for swimming and grabbing, and Air for flying).

However, while it is ''the'' worst example in the game, others are just as poor.  The Pact of the Chain warlock's familiar, for instance (which ''also'' needs the PC to expends his or her own options to allow it to attack) similarly suffers from the lack of scaling of any kind, and the major benefit offered by such a companion (Magic Resistance) is undercut by the familiar's tendency to die messily in any kind of AoE attack.  It is arguably the weakest warlock Pact option in the game for this reason. 

Plus, if you want to play a summoner using just the core books... don't.  The ''Player's Handbook'' in particular offers only a few, fairly weak summoning spells, which in turn can summon only a few, fairly-weak creatures with very poor scaling.  ''Xanathar's Guide to Everything'' added in a lot more, but even they won't fish you enough to really get out ahead.  Indeed, it hurts the Conjuration wizard simply by virtue of him having a lot of class features that boost summoning, but summoning spells being toss.

Most players agree that companion/summoning abuse absolutely ''was'' a problem in 3.5 that needed addressing... but few of them dispute that 5e's method of doing so was ham-handedly attempting to make the entire style of play weak and useless rather than bringing it truly into line.

The March 2019 UA (and Tasha's Cauldron of Everything, where it was published) appears to have been at least partially themed around fixing this, with largely well received results, doing everything the rest of the addition has been in terms of introducing well-designed, properly scaling summoning spells. This was done by making the summons basic creatures that can scale more consistently and slapped on a special template (So using Summon Celestial lets you slap a Avenger or Defender template, Summon Elemental slaps on element templates, etc.).