If you fear of turning conjures into engineer kits, maybe change the entire conjure set to full support. Instead of having 4 conjure weap skills you have one glyph like skill that drops one conjure based on attunement, allowing you to drop a conjure based on the situation in order to aid a team mate. You can also add 3 more conjure spells that are similar, like: conjure shourd -stun breaker for you that gives you and everyone around an aura, conjure armor – can give stat boosts, conjure boots – gives different effects on each step(like engie slick shoes).
Make conjures give the ability for eles to share their diversity and ability to adapt to any situation with their team. Making conjures work more like engie kits goes away from what they were designed to be in the first place.