I've just received a private message from someone that has given the his reasons for keeping the seal in tact, many of which I've been tackling with myself, so though I would post it here;
"First off it´s important to say that I´m ALWAYS on the side that´s supporting to preserve the History of the Battle Beasts rather than fooling around with it so that obviously means I´d suggest you NOT to open the seal. But why....
I understand that this might´ve been quite a big purchase knowing todays value of those sets and that you´ve done it with the intention to check a couple of the high end Beasts from your list. From that point of view that´s a great score and eventually you might even be better of buying the set since if you´d have had to hunt them down loose prices would´ve added up quickly as well. BUT if you´ve to leave them sealed in the pack I get it might be a bit hard knowing you have them but on the other hand you can´t get to them... That´s a tough position to be in and that´s also the main reason why some do open a sealed package, understandable on one end but a shame on the other.
Sealed packs are becoming harder and harder to find and although there´s enough tempting reasons to open it there´s an equal amount of reasons for not doing so. For some a seal is just a little tape that´s easily cut through and it´s not a big deal but for others the seal is much more than that since it´s exactly that little tape that´s the difference between having a piece from the past in hand or holding a piece of history in its original state. Of course as some already stated from a value point of view the seal can make a big difference which in time will become over bigger so cutting that single tape makes a big difference when it comes to value. Apart from that, and maybe more important, is the fact that there´s always some kind of mystery surrounding sealed packs or box sets knowing you´ve this original piece of untouched History. Those figs have been inside that pack since they left the factory in China and the decision whether to break that seal and take them out for the first time in almost 30 years is on your shoulders... Taking them out gives you the feel you do have them in hand whereas leaving them inside doesn´t eventually make a whole big of a difference because in the end they´ll probably end up back inside or being displayed outside the box. The only difference is that in one case you break the seal and a part of the mystery and history that came with this set disappears while on the other hand you leave the seal intact and it stays as it is. In the end it´s just the mindset imo and what you think is most important to you but also for the future. In 30 years none has been tempted, or dared, to break the seal meaning they probably had a good reason for that.
I hope you will leave the set intact and find the inner peace to display it as such preserving the history and leaving the mystery surrounding this box intact.
In the end it´s all up to you but it´s important to realize that cutting the tape is more than just cutting the tape
Enjoy the Beasts!
ps. In some case the tape has become so old/yellowed/aged that it´s about to fall of in which case the seal would be broken as well (due to aging). And even though the result is the same the feel is different since it´s something you can´t prevent so maybe time will tell..."