I have made around 5-6 kits from Wine expert (Select Amarone, Valpolicella, Merlot, Eclipse Nebbiolo, Eclipse Forza) and another 2 from others (Chianti, Nebbiolo) vendors.
Generally speaking, the kit taste is something I noticed as well and is nothing more than youth. Red wines take time to mature, and no red wine kit is going to give you the best taste 2 months after you make it or even 6 months in my experience regardless of the series (low end to eclipse) just like real wine. There is only so much that we can do to speed up the maturity of the kit. The one white I made (Gurwertraminer Wine Expert) was good a month after, however.
My experience is that the reds taste similar when they are young, and the more expensive the kit, the longer it takes to mature, and the more aeration they need straight out of the bottle to open up like any red wine.
Some folks have given good advice already. Buy the kits with grape packs, with the most juice up front as possible. Those are always the best. The reds start to shine 18 months to 24 months after you are done secondary fermentation. I added extra French wood (medium toast) to the Merlot I mentioned above and only a year later can I taste the extra oak I added.
Weak body? Check your notes and take a look at the starting SG and FG. Weak body can be amended by adjusting plain table sugar through chaptalization to bump up the alchohol If the starting SG is low (check online for directions and amount). You can also add extra wood, and get the dried grape packs to add to the wine.
What commercial wine are you drinking? take a look at the ABV. If you are drinking 13.5-14% ABV wine, which isn't all that common for reds like "Apothic" as compared to commercial wine from 20 years ago, you will think your kit is low in ABV if its shooting for 12.5%.
A note on yeast - every one of the wine kits I have bought come with at least one Lavalin EC-1118 packet. The more complex Eclipses can come with an extra packet of more specialized yeast. If you are going to chaptalize, do it a day after the wine has started vigorous fermentation. You don't want to shock the yeast. EC-1118 yeast can be used to finish off any fermentation that doesn't finish or if you want a dry wine. Its a work horse yeast that is capable of 18% ABV.
As an example, right now I am making a Brunello di Montalcino from a San Giovese di Montalcino Legacy kit that didn't even come with oak chips (package says tannin extract in lieu of oak) or grape pack. Starting SG was targeting 12.7% ABV and I adjusted it up to 14% ABV or so. I bought this kit in Canada for about 80 American with wood and grape pack I am looking at less than $100. Not bad for 30 bottles.
Please note that Wine Expert is the same company as Legacy. In fact, many of the kit producers are the same company out of Canada and people don't even realize it.
These kits time wise are a deal. Brunello is traditionally a 4 year venture from grape to bottle as is Barolo and Amarone. On a side, note I have also started making beer. Waiting 6 weeks to make a decent lager is child's play compared to wine making.
What a fun hobby beer and wine making is.
AR