I like pets and additional party members, as long as neither are required to be successful at the game. The option to have either is a big plus in my book.
Additional party members are fun, because they (should) already have dynamic personalities that (can) affect how you make decisions and how the game plays out. They're also just fun to manage because using them allows you to try out different classes or builds or playing-styles within one game run-through. Think Baldur's Gate II, Dungeon Siege II, Planescape:Torment.
Pets are fun, whatever the means of developing them. To an extent, they fill the gap left when there are no other companions. Not that going it alone is bad thing - I don't really like multiplayer games at all, for example. I always eventually, if not at first, play with the pets available in any RPG - From the Necro and Druid from Diablo II to the summoning skills and dolls of the Larian games...Sacred, Titan Quest, Dungeon Siege II, pretty much every action RPG has them. I'm stoked to see the Frankenstein-creation style in Ego Draconis. I hope it's implemented well.
I also hope to see an additional party member or two added, if not for the game's duration then at least for some quests or battles.
