I'm not going to say that I am an expert on the Summoner class- I'm far from it- but I can give you the perspective of someone who's played a Summoner until he's reached Necromancer (20th level) status.
From what I've seen so far, the pets are markedly weaker than they were in EQ1. I'd guess they are roughly 60% as effective. I'd LOVE to have my EQ1 Necropet with me instead of the bag of bones I have now. I think he does have some taunt ability but it is extraordinarily easy for me to toss off even a small nuke or to apply more than one dot and get aggro from my pet and the pet then cannot get aggro back from me. The best explanation of the situation I've gotten from anyone told me to consider my pet as a minor DoT and nothing more.
I do have some suggestions, including one major one: keep your pet summon spell at App3 or Adept if at all possible. If you're staying with the App1 version of your spell, you essentially have a lesser green pet. Taking it to App2 gives you a lesser blue pet and App3 gives you an even-con pet (until level 19 when the pet goes lesser blue to you). That really does help. At 20, unfortunately, you get a totally new summoning spell that makes the pet lesser blue to you again- and the App3 version of the spell costs almost 2gp! No chance of me affording that anytime soon so I'll have to go with the weaker pet. And yes I consider that a huge disadvantage for the class.
As the poster pointed out above, be very careful when conning your enemies. A ^green mob group mob is tougher than a yellow solo mob. Yes, it's a pain to constnatly have to find solo mobs but it's far safer. Let your pet beat on the mob and get beaten on by the mob for several turns before you do anything at all- pets seem to build aggro far slower than players do- and go with your DoTs first (nukes almost instantly get you aggro). Be ready to toss a pet heal spell if the pet takes damage sufficient to go into the yellow or orange (interestingly, Sooth Servant is one spell that doesn't need upgrading. I did upgrade to App3 and found that, whenever I cast it, I get aggro now). Once the mob is less than 50%, you can nuke it down and -probably- not get aggro or, if you do, you can -probably- kill it before it kills you.
Playing the Summoner in EQ2 means that you have to unlearn alot of things from playing a pet class in EQ1. Kiting is a thing of the past. Sitting down and watching your pet take down an enemy is a thing of the past. Root Bombing >does< work. But, honestly, the best advice I can give when it comes to soloing is Don't Do It. It's a game almost totally geared toward grouping and away from efficient soloing- unless you like a steady diet of greens and blues. You do have some group-friendly spells (Gift Of The Magi, Earthly Brand and others), so try your best to group up whenever possible.