You might want to look into the babyhawk Oh Snap - which is the SSC version of the babyhawk mei tai (designed from about 7kg to toddler).

Haven't used either, but have used a catbirdbaby mei tai, which is of a similar body shape etc to the pikkolo. The CBB carriers are shorter bodied with a narrow strap angle on the shoulder straps - they are in their element with smaller/younger babies and narrow shouldered or petite wearers. You can also get the CBB support belt which allows the carrier to be worn non-apron style (like an Ergo), which gives more support for heavier babies/toddlers as well as extending the body length. To the best of my knowledge though, you cannot use the support belt when forward facing, as you can't cinch the waist in whilst using the belt. (I've used the support belt on other mei tais and it is comparable with an Ergo waist for support).

I would say that an Oh Snap is going to give you greater longevity, especially as E gets older. Are you particularly keen to do forward facing carries, or are you just finding inward facing carries a bit limiting now that E wants to look around? Depending on how heavy E is, you might find that you don't get much use out of a carrier capable of forward facing. Personally I find that they are not very comfortable for the wearer in any carrier, as the baby's weight is not distributed evenly. As a baby gets older I find back or hip carries much more comfortable, they still allow the baby to look around but in a more natural carrying position, and they can still turn in to snuggle when they want to. I used (and still use) a Scootababy for DS - it's a toddler suitable SSC/dedicated hip carrier and is probably the most comfortable one on the market. I've worn him all day (as in, for nearly eight hours straight) in it and that was when he was nearly 13kg. If you are finding that an Ergo is not suitable yet for back carries because E is sitting too low on your back to be able to see, something like an Oh Snap or Pikkolo can be worn higher on the waist than an Ergo, which is generally worn on the hips.

So you might find that your hotsling is more useful for the looking around stage - as you can carry in a hip carry or a buddha carry. And it's pretty light and portable, so you could always have the hotsling for 'visible' carries and pack a meitai or SSC for sleeping.

Just something to consider, but if you are really keen to have a carrier capable of forward facing, then the pikkolo is your best bet. It may not be the best choice in terms of longevity though.

ETA: if E is looking like she's going to be tall, an Ergo is a relatively short bodied carrier so although it's supportive enough for toddlers, some people (including myself) don't find it tall enough in the body for tall toddlers. This is where a babyhawk MT would be a good option.

HTH!